Citing a lack of 'trust' in how the BBC is handling what she terms a pay 'crisis', she said she had "abruptly" left the Beijing bureau last week after four years.
She will appear as a guest presenter, alongside John Humphrys on BBC Radio 4's flagship Today show this morning.
BBC Women, a group of more than 150 broadcasters and producers, said: "It is hugely regrettable that an outstanding journalist like Carrie Gracie feels she has no option but to resign from her post because the BBC has not valued her equally. Up to 200 women that we know of in various grades and roles have made pay complaints."
Hundreds of senior BBC women pledge support
After the news broke #IStandWithCarrie trended on Twitter as social media users and fellow BBC staff members showed their support for the broadcaster.
MGracie's 1400-word letter published on her blog tonight, also explained how she had discovered the BBC's male international editors "earned at least 50 per cent more" than the female ones.
Addressing the letter to the BBC audience, she wrote: "With great regret, I have left my post as China editor to speak out publicly on a crisis of trust at the BBC.
"The BBC belongs to you, the licence fee payer. I believe you have a right to know that it is breaking equality law and resisting pressure for a fair and transparent pay structure."
She went on to blast the BBC's response to the controversy surrounding its publication of talent pay above £150,000, particularly surrounding the gender pay gap and the vast salaries for the top presenters.
She wrote: "The outgoing Director of News said last month, 'We did a full equal pay audit which showed there is equal pay across the BBC.' But this was not a full audit.
"It excluded the women with the biggest pay gaps. The BBC has now begun a 'talent review' but the women affected have no confidence in it. Up to two hundred BBC women have made pay complaints only to be told repeatedly there is no pay discrimination at the BBC. Can we all be wrong? I no longer trust our management to give an honest answer."
She claimed "up to 200 women" have made complaints in the last six months since the BBC disclosed the pay details of its top earners.
She added: "It is not men earning more because they do more of the jobs which pay better. It is men earning more in the same jobs or jobs of equal value," she said in her letter.
Gracie, who mentioned the difficulty of living 5000 miles away from her two teenage children during her time in Beijing, has worked for the BBC for 30 years.
In September 2011, she left the BBC to undergo cancer treatment, returning to the BBC News Channel the following May.
However, when James Harding - BBC director of news and current affairs - offered her the role of China Editor in 2013, she said he insisted that she be paid the same as her male counterparts.
Miss Gracie has received floods of support from other journalists since the news broke earlier this evening.
News of the departure was swiftly retweeted by senior BBC journalists including Newsnight presenters Emily Maitlis and Kirsty Wark, as well as Victoria Derbyshire.
Soon after 134 female journalists issued a statement saying they 'wholeheartedly support' Gracie and that the BBC must act quickly on the gender pay gap.
BBC workers also tweeted commending Miss Gracie.
Maria Byrne, a senior BBC producer called Miss Gracie 'the best of the BBC' and that she was 'talented, hardworking and always asking tough questions'.
BBC News North America Correspondent, James Cook said Miss Gracie stepping down as 'a huge loss to the BBC' and described her as 'highly principled and extremely talented'.
Rachel Kennedy, an editor at BBC News said it was a 'huge loss' and she was 'always proud to work with Miss Gracie.
The BBC's top earners
1. Chris Evans £2.2m - £2.25m
2. Gary Lineker £1.75m - £1.8m
3. Graham Norton £850,0000 - £899,999
4. Jeremy Vine £700,000 - £749,999
5. John Humphrys £600,000 - £649,999
6. Huw Edwards £550,000 - £599,999
7. Steve Wright £500,000 - £549,999
= 8. Claudia Winkleman £450,000 - £499,999
= 8. Matt Baker £450,000 - £499,999
= 9. Nicky Campbell £400,000 - £449,999
= 9. Andrew Marr £400,000 - £449,999
= 9. Stephen Nolan £400,000 - £449,999
= 9. Alan Shearer £400,000 - £449,999
=9. Alex Jones £400,000 - £449,000
10. Fiona Bruce £350,000 - £399,999