Son says days after mother's death a blank

An Adelaide man charged with the murder of his mother says the days after the alleged killing are "close to a blank in my memory".

Wei Li, 22, has told his Supreme Court trial that he was making spontaneous decisions when he fled Adelaide, first for Melbourne and then Singapore and China in 2011.

In cross examination on Thursday he repeatedly said he could not recall or did not remember many of his actions, including contacting bus and rail companies.

The court also heard he ignored more than 100 phone calls from his father and other calls from police.

But he denied prosecution allegations that all his actions were designed to evade authorities and said he only wanted to get to his father and his extended family in China.

He said for much of that time he was also "blind drunk".

"Those days are close to a blank in my memory," Li said.

The former law student is on trial for the murder in 2011 of Emma Tien.

The prosecution has alleged Ms Tien, 41, was beaten with a metal rod and strangled before her body was wrapped in bloody bedsheets and left in the lounge of the family's Burnside home.

Li was 18 at the time of his mother's death and studying law at university.

He was returned to Australia in 2014 after being detained by Chinese authorities.

In his evidence on Wednesday, Li said he had acted in self-defence when his mother came at him, yelling and screaming after becoming angry because he was not practising piano.

"It happened so fast. At some point I realised she had something in her hand, just going at me," he said.

"I think she wanted to kill me. I had no choice but to fight back."

The trial continues.