Helicity-dependent　photocurrent　(HDPC)　of　the　topological　surface　states　(TSSs)　in　the　intrinsic　magnetic　topological　insulator　MnBi2Te4　is　investigated.　It　is　revealed　that　the　HDPC　is　mainly　contributed　by　the　circular　photogalvanic　effect　(CPGE)　current　when　the　incident　plane　is　perpendicular　to　the　connection　of　the　two　electrodes,　while　the　circular　photon　drag　effect　plays　the　dominant　role　when　the　incident　plane　is　parallel　to　the　connection　of　the　two　electrodes.　The　CPGE　current　shows　an　odd　function　dependence　on　incident　angles,　which　is　consistent　with　the　C　3　v　symmetry　group　of　the　TSSs　in　MnBi2Te4.　The　amplitude　of　the　CPGE　current　increases　with　the　decrease　in　temperature,　which　can　be　attributed　to　the　increase　in　mobility　at　low　temperatures,　confirmed　by　the　transport　measurements.　Furthermore,　we　modulate　the　CPGE　of　MnBi2Te4　by　applying　top　gate　and　source-drain　voltages.　Compared　to　Bi2Te3　of　the　same　thickness,　the　CPGE　current　of　MnBi2Te4　can　be　more　effectively　tuned　by　the　top　gate　because　the　Fermi　level　of　MnBi2Te4　can　be　effectively　regulated　by　the　top　gate,　and　it　is　tuned　across　the　Dirac　point.　This　work　suggests　that　the　intrinsic　magnetic　topological　insulator　MnBi2Te4　is　a　good　candidate　for　designing　opto-spintronics　devices.