A new kind of triaxial air bearing test bed based on Variable-Speed Control Moment Gyro(VSCMG) was described for satellite attitude determination and control system simulation.A triaxial air-bearing platform newly developed was used as the test bed and a cluster of four variable speed control moment gyros was constructed in pyramid mounting arrangement as a main actuator in the simulation system.Also the system used the six gas thrusters to assist VSCMGs to avoid singularity.The attitude determination system was introduced,which consists of three fiber optical gyros,a horizon sensor and a magnetometer.The main parameters of all parts were given to illustrate that the platform can be used in the simulation and validation of many algorithms for modern agile small satellite,which can provide reference for other facilities in this research field.