Sarah Jessica Parker is a real life Kojak ... with better hats ... because she found the guy who lost a $4,700 check on a New York street.

Sarah was walking in the West Village last week when she looked down and saw the check laying on the sidewalk.  

She had the name of the payee and did some serious Googling and tracked down their address.

And get this. Sarah's been trying to contact the payee but he or she isn't home. She says she'll keep trying.

Who loves ya, baby?