The invention discloses a load testing system for a loader working device. The load testing system comprises a loader working system and a load testing system, wherein the working system is composed of a bucket, a rocker arm, a connecting rod, a boom, a hydraulic cylinder, a pin shaft and the like; and the load testing system is composed of a torque testing module, a stress testing module, a displacement testing module and the like. According to the load testing system for the loader working device disclosed by the invention, the three-dimensional torque is measured by a pressure sensor in the torque testing module and a relative position thereof; the three-dimensional stress is measured by the pressure sensor, a bidirectional pin shaft force sensor and an annular electric coil force sensor; and the position and the attitude of the working device are determined by a displacement sensor. The load testing system can simultaneously measure the three-dimensional stress and the three-dimensional torque which are applied to the working device, and three-dimensional torque decoupling is realized through innovation of a mechanical structure. According to the testing scheme disclosed by the invention, the limitation of the traditional testing method is broken through, and the measuring process is simplified; and in addition, a part of testing modules can be reused, so that the testing cost is lowered, and the testing efficiency is improved.