The invention discloses a heavy rainfall induced rock landslide field model testing device. The device comprises a rainfall system, a rain gauge, a flow controller, an artificially excavated crack, a simulation water line, a back edge crack water level, a clay compaction layer after artificial grooving, a natural soft interlayer, a stable bedrock layer, an upper rock mass, sensors, a drain pipe, an anti-slide pipe, a water pump, a water supply pipe, a control valve, a water meter, nozzles, three-way pipes, four-way pipes, two-way pipes, branch pipes and main pipes. The device eliminates errors caused by artificial production of slide zones and can simulate the effect degree of different rainfall degrees to landslides; the model has controllable structure size and has the characteristics of being high in flexibility, convenient to construct, short in period, capable of being reused and the like, and the cost is saved.