The invention discloses an automatic adjustment load testing system of a self-counter-force cross beam. The testing system is mainly applied to teaching and scientific research of roads and bridges ofcivil engineering specialty and used for loading and testing of unfolding structures and members. The system consists of a self-balancing counter-force frame, a microprocessor controlled electro-hydraulic servo loading system (including control, displacement and force acquisition software and a hydraulic oil source), an electro-hydraulic servo actuator and a control cabinet. The device deformation of the system meets the existing specification and regulation requirements of relevant testing devices, device members do not produce obvious deformation themselves under a maximum pressure, it is ensured that their deformation is in an elastic range, and no plastic deformation is produced; the system has displacement and testing force overload protecting functions and software and hardware protecting functions, adopts servo system control and can execute force, displacement and deformation closed-loop measurement.