Sources close to the investigation say a post-mortem examination revealed the Chinese-born international student had suffered more than 30 stab wounds.
Mr Barrett’s lawyer Bill Whitby says the man is struggling in custody and would eventually make an application for bail.
“He’s very upset, shocked,” Mr Whitby said outside Burwood Local Court on Wednesday.
“He will be pleading not guilty.”
Ms Leng was last seen catching the train home to the Sydney suburb of Campsie on April 21, where she lived with her 48-year-old aunt and Mr Barrett since arriving in Australia five years ago.
A representative for her family, Peter Chen, said the slain international student, who was also known as Michelle, was well loved.
“Michelle is quite a good person,” he said.
“Like an angel.”
Ms Leng’s story has attracted media attention in China.
Her mother has flown to Australia since the death.
Mr Barrett’s matter is due back in court in next month.