The wife of accused murderer Lian Bin Xie has told his trial that he did not leave their bed at any time on the night he allegedly beat and strangled five members of her family to death.

In an important passage of evidence in the long-running NSW Supreme Court trial, Kathy Lin told the jury on Wednesday her husband "didn't leave home" at any time on the night of July 17, 2009, or in the early hours of the following morning.

Lian Bin Xie, also known as "Robert", is accused of sneaking out of his house in Beck Street, North Epping, travelling the short distance to his brother-in-law's Min Lin's home, and then murdering Mr Lin, his wife, sister-in-law and two young boys as they lay in their beds.

He has pleaded not guilty to the killings.

Having been called as a prosecution witness in the case on Wednesday, Mrs Lin, 43, said her husband had been home the entire night.

"Do you know whether or not Robert got out of bed that night?" Crown prosecutor Mark Tedeschi, QC, asked.

"As I know, no," Mrs Lin replied.

"Do you know whether or not Robert left the house that night on the 17th and 18th of July?" Mr Tedeschi continued.

"No, he didn't leave home," Mrs Lin said.

"Do you know if he went out in the car that morning before you got up?" Mr Tedeschi asked.

"We are same time getting up, he didn't go out," Mrs Lin replied.

"Did you feel in any way sedated before you went to sleep that night?" Mr Tedeschi asked.

"No, I just was normal that night, " she replied.

Later in her evidence Mrs Lin broke down as she described arriving at her brother's home and discovering his wife Lily Lin's body in her bedroom.

Mrs Lin said she and Mr Xie arrived at the home on the morning of July 18 to find the door unlocked and no answer from anyone inside.

When they went in and found Min Lin's watch and wallet on a table but the ground floor otherwise deserted, they went upstairs to his bedroom.

"We called my brother and then go into his bedroom," Mrs Lin said.

"My husband asked me not to look and he hugged me but I'd already turned.

"I saw blood ... I saw my sister-in-law."

Mrs Lin broke down, and despite being given a short break, was unable to continue her evidence.

She will return to court on Thursday.