The invention discloses a solar public fitness device for exercising leg muscles. The solar public fitness device comprises a center vertical column, leg extension mechanisms are arranged on the periphery of the center vertical column, each leg extension mechanism is provided with a square frame, a fixed bearing, a rotating shaft, an inclined frame, a seat, an armrest, a buffer pad, a waterproof film, a fixing clamping belt, a fixing frame, a stopper, a rubber pad and a movable pedal frame, each movable pedal frame is provided with a sliding rail, a baffle plate, a pedal frame body, a small fixing bearing, a pulley, a connecting shaft, a small electric telescopic rod, a saw-toothed stopper, a saw-toothed groove, an adjusting linear motor and a telescopic end. The solar public fitness device is provided with a solar power generation mechanism, an intelligent control mechanism is arranged on each inclined frame, each intelligent control mechanism comprises a storage plate, a controller, a capacitive display screen, music play software, a loudspeaker, an on / off key, a PLC (programmable logic controller) system, a signal receiver, personal information recording software, a pressure sensor and a signal transmitter. The solar public fitness device has the advantages of simple structure and high practicability.