The invention discloses a quadruped robot platform which comprises a body module and a leg module. The quadruped robot platform is characterized in that the leg module is arranged as a planer five-rod mechanism flexible leg and comprises a pitching driving joint module, a connecting rod mechanism module and a toe module, wherein the pitching driving joint module comprises a rigidity-variable driving flexible joint, a driving motor, a harmonic reducer and a synchronous belt; the harmonic reducer and the driving motor thereof are mounted on a same supporting frame; one harmonic reducer is integrated with the rigidity-variable driving flexible joint to be taken as an output; the toe comprises a three-dimensional mechanic sensor, a three-dimensional mechanic sensor bracket and an arch; the connecting rod mechanism has 10 hinge points of (A), (B), (C), (D), (E), (F), (G), (H), (R) and (I); the 10 hinge points are utilized to hinge the connecting rods into a conventional four-connecting-rod mechanism, a four-connecting-rod mechanism with a spring rod and a planer pentagonal five-connecting-rod mechanism.