Mr Marris stomped his feet and sobbed in anguish at times while reading his victim impact statement to the court.
"You were doing something with your phone, people were seriously hurt and crying around," he said, recounting the day of the crash.
"I could see Kimberley holding Ruby screaming, 'somebody help'.
"I see Ruby getting paler and paler as her internal injuries were starting to take effect and the blood was draining from her body."
Ruby's death had left the family and the wider community heartbroken, he said.
"There was no remorse from you that day," Mr Marris said to Cao.
"You were probably in shock but there were people dying from your actions.
"I got told Ruby died while lying on the road. You would have heard me scream. It took three people to hold me down with a broken back."
Cao's assertion he was tired was a "feeble excuse", Mr Marris said.
"She was only 5, Mr Cao."
The Marris' two other children Georgia, 9, and Sophie, 7, suffered moderate injuries.
The injured family members were taken to Dunedin Hospital.
Cao's 60-year-old mother, who was a passenger in Cao's rented four-wheel-drive, was also seriously injured and was taken to Oamaru Hospital.
The tourist pleaded guilty on April 15 to one charge of dangerous driving causing death and five charges of dangerous driving causing injury.
Cao also received sentences of nine months in jail for each of the five charges of dangerous driving causing injury. They will be served concurrently.
At his last court appearance, Cao was warned imprisonment was likely and to prepare himself accordingly.
Dangerous driving causing death is punishable by up to 10 years' imprisonment.
Cao had travelled to Moeraki after arriving in Auckland on February 17 with his partner and parents.
He hired a Ford Ranger in Auckland to tour New Zealand.
Cao spent the night of February 20 in Christchurch and left about 10am to travel to Queenstown.
The family stopped at the Moeraki Boulders to take photographs before continuing their travels about 4.50pm.
About 1km after turning on to State Highway 1, Cao crossed the centre line.
As he approached the brow of a hill on the highway, he saw the Marris family's vehicle.
The drivers of both vehicles attempted to avoid each other, but veered in the same direction and collided head on.
There was little traffic on the road at the time. The weather was fine and the road was dry.
The section of road was marked with yellow no-passing lines.
