The 30-year-old replaces fellow South African JP Duminy, who is unable to take up his contract after his IPL side Hyderabad Sunrisers qualified for the Champions League T20 competition in September.
Amla currently heads the ICC player rankings for both test and one-day internationals. He scored his highest test score of 311 not out against England at Surrey's Oval ground in July 2012.
"The Oval holds a lot of fond memories for me. I look forward to returning there this year and hopefully enjoying similar success," Amla said in a statement on the club's website (www.kiaoval.com).
He will be the third overseas player at Surrey this season after Proteas captain Graeme Smith and Australian veteran Ricky Ponting and will make his debut at Durham on Aug 22.
Image: Hashim Amla
Photograph: Grant Pitcher / Gallo Images / Getty Images
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