We　present　a　systematic　investigation　of　helicity-dependent　photocurrent　(HDPC)　in　epitaxial　PbTe　quantum　wells　(QWs),　revealing　a　striking　transition　in　the　dominant　mechanism　upon　Pb　doping.　While　the　undoped　QW　exhibits　predominantly　the　circular　photon　drag　effect,　Pb　doping　triggers　a　crossover　to　the　circular　photogalvanic　effect.　This　transition　is　mainly　attributed　to　the　doping-enhanced　spin-orbit　coupling　(SOC)　strengths.　Crucially,　the　absence　of　HDPC　when　the　photocurrent-collecting　electrodes　are　aligned　within　the　laser　incidence　plane　provides　rigorous　confirmation　of　the　system＇s　C　3　v　symmetry,　excluding　extrinsic　symmetry-breaking　artifacts.　Quantitative　analysis　of　the　Rashba-induced　effective　electric　field　(　α　e　)　reveals　distinct　temperature　dependence:　the　Pb-doped　QW　exhibits　a　positive　correlation　between　the　SOC　strength　and　temperature,　whereas　the　undoped　QW　shows　a　negative　trend.　Furthermore,　bias-dependent　modulation　demonstrates　superior　HDPC　tunability　in　the　undoped　QW,　facilitated　by　its　higher　photocarrier　concentrations.　These　findings　establish　PbTe　QWs　as　a　promising　platform　for　opto-spintronic　device　design.　©　2025　Author(s).