Buick's previous best was 170 winners in 2021, when he narrowly lost out to Oisin Murphy in the title race.
After taking the title for the first time in his career this autumn, the rider had been closing in on the milestone as the year reaches an end.
Zealot, trained by Michael Appleby, was one of two rides for Buick on the evening all-weather card and the gelding immediately carried him to his double century when securing the Spreadex Sports First Goalscorer Insurance Handicap.
"I said to Tony (Hind), my agent, six weeks ago when we had 31 winners to go that it was within reach," Buick told Sky Sports Racing.
"Things didn't quite go to plan until today, but it's great and I've had lots of support. Thank you to everyone.
"It's been a great year. I've had wonderful support from everybody. Charlie Appleby and Godolphin have had an amazing year with Charlie also being champion (trainer) as well.
"I would love to go for it again next year, beyond that you never know."