Michael Edwin Preston, 60, was this afternoon found guilty of murder following five weeks of frequently graphic, bloody and highly emotional testimony in the High Court at Wellington.
The jury took less than four hours to reach its verdict, which was greeted by cries from the public gallery.
Preston, who was also convicted of breaching a protection order, remained stony faced and silent in the dock as he learned his fate.
Ms Fan, 37, was stabbed 38 times in a frenzied attack in her home in the Wellington suburb of Miramar in November 2013.
Her body was later found lying in a pool of blood on the laundry floor.
The Crown had argued Preston killed Ms Fan to gain sole custody of the couple's two children.
Detective Senior Sergeant John van den Heuval said the verdict would be welcomed with great relief by Ms Fan's family and friends, both in New Zealand and China.
"Our thoughts are with the children now who must grow up knowing their father murdered their mother. That's going to be difficult for them, but they are surrounded by people who, like Mei, love and care for them deeply," he said.
"Having Michael Preston locked away for a long, long time is also very important to ensure the wellbeing and safety of the children as they grow up."
Mr van den Heuval said finding justice for Ms Fan had taken a long time.
"It's been a couple of years in the making," he said.
"It was very complex - it was a whodunit, and it involved many, many hours of investigation."
The investigation team went offshore to Australia, China and inner Mongolia to gather the evidence needed to convict Preston, he said.
Summing up for the jury earlier, Justice Joseph Williams acknowledged the heinous impact Ms Fan's death had on Ms Fan's and Preston's children.
"They were caught up in a nightmare scenario not of their making and probably not fully understood."
On Friday, Crown prosecutor Grant Burston said Preston had "three windows of opportunity" to murder Ms Fan, adding her killer must have "really hated" her.
The trial heard Ms Fan told a police officer she was worried about Preston's reaction if she succeeded at getting custody of the couple's two children.
