Former Blackburn Rovers Chief Executive John Williams will replace Jeremy Peace, who has been chairman of West Brom for 14 years, with immediate effect, the Premier League club said in a statement on its website. (www.wba.co.uk)
Peace will stay on at West Brom in an advisory role to help with the transition, but has relinquished his position on the club's board.
Lai, who describes himself as a lifelong football fan, said the takeover was "a great investment".
"I am excited and privileged to have the chance to become the new owner of this great club," he added. "We have a strong squad, loyal fans and a unique culture.
"My immediate priorities will be to maintain the club's stable structure, respecting its well-run nature and its heritage. I have no intention of changing the club's ethos."
China has been pouring money into football across the world, as the country's President Xi Jinping looks to make them a global powerhouse in the sport.
The deal is the latest move by Chinese investors to make inroads into the lucrative Premier League, which is flush with the money from a bumper TV rights deal that kicks off from the 2016-17 season.
In May, English football club Aston Villa, who were relegated from the Premier League at the end of last season, announced that they had agreed to a takeover by Chinese magnate Xia Jiantong.
(Reporting by Simon Jennings in Bengaluru; editing by Sudipto Ganguly)
