A new calibration method for Inertial Measurement Unit (IMU) of strapdown inertial technology was presented. IMU has been composed of MEMS accelerometers, gyroscopes and a circuit of signal processing. Normally, a rate transfer test and multi-position tests are used for IMU calibration. The new cali- bration method is based on whole angle rotation or finite rotation. In fact it suggests to turn over IMU around three axes simultane- ously. In order to solve the equation of calibration, it is necessary to provide an equality of a rank of basic matrix into degree of basic matrix. Normally MEMS gyroscopes have got g- and g2- drifts. It is proposed a way of finding such drifts. The results of simulated IMU data presented to demonstrate the performance of the new calibration method.