The Sri Lankan shared a second-wicket stand of 187 with opener Rory Burns (80) as Surrey reached 394-5 at stumps.
Sangakkara was dropped at first slip by Craig Overton on nine but went on to hit 24 fours and four sixes to register his 56th first-class century.
Jason Roy hit an attacking 85 before he was out lbw to seamer Lewis Gregory in the final over of the day.
Sangakkara passed 1,000 first-class runs for Surrey in just his 22nd innings before he was out caught at deep cover by Overton off Tim Groenewald.
Zafar Ansari, making his return from a dislocated thumb sustained against Lancashire late last season, struck five fours in an unbeaten 28 before play ended.
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Surrey batsman Kumar Sangakkara told BBC Radio London: "I think after the Nottingham game it was important we got off to a good start in the first game at home.
"They way everyone went about their batting, the application and the intent they showed, was very good.
"Burnsy and Jason were outstanding. It was very easy to bat with them because they kept putting pressure on the bowlers and putting the bad balls away.
"It made my batting a lot easier for me because I saw a positive intent all the time from the other end."
Kumar Sangakkara hit a superb 171 as Surrey's batsman dominated the opening day against Somerset at The Oval.