Top Shop, Next, Apple, Prada, Hollister, Nike, Hugo Boss and Mulberry are among the retailers due to open stores at the centre.
Westfield Stratford City will provide the only access to the London Olympic Stadium and large screens along the centre's walkways will display the main sporting events.
Olympic medallist Colin Jackson will launch the first new Lloyds TSB branch since 2004 and customers will be able to have their photo taken with the 2012 Olympic torch.
Bill Giouroukos, director of operations at Westfield, said: "The retail mix we are putting in place at Stratford will be the next chapter in retail development for London.
"We have secured a number of leading retailers who will be complemented by the extensive dining, leisure and entertainment offer we are creating to make Stratford City a lifestyle destination and a new metropolitan centre for east London."
The shopping centre is set to become one of the best-connected retail destinations in the UK, with £17 billion being invested in public transport in the lead-up to the 2012 Olympics.
Mayor of London Boris Johnson, who will help cut the ribbon at today's launch, said: "Westfield's Stratford City project is setting the pace for the transformation of east London. It is one of the most important legacies of the 2012 Olympics.
"It will create 18,000 jobs and, as a result of Westfield's investment, have some of the most modern additions to London's public transport infrastructure."
Westfield's sister site in Shepherd's Bush launched two years ago and attracted 23 million visitors in its first year.
- AAP
SHOPPING MONSTER
* Westfield Stratford City is a £163;1.45 billion development comprising 176,500sq m of retail and leisure, as well as 102,190sq m of office space, three hotels and homes.
* The shopping centre is next to the Olympic Park and will form the gateway to the Olympic Games in 2012.
* Up to 8500 permanent jobs will be provided by the retail sector at the shopping centre.
* There will be 300 fashion, food and lifestyle brands.
* There are 5000 car parking spaces on site.