Because of the deformation of shock absorbers, the dither RLGs inertial measurement unit (IMU) can not be calibrated using a precise turntable as attitude reference.This paper introduces a new calibration method for dither RLGs IMU,firstly, the RLGs were turned off and the IMU without absorbers was fastened on a precise turntable to calibrate the error parameters of accelerometers;then the shock absorbers were installed on IMU,paper designed a procedure for the calibration of RLGs error parameters. Further more,according to the output error equation of the RLGs, a systematic calibration algorithm of the RLGs IMU was proposed based on a 21 dimensional kalman filter using velocity errors as measurement vector.The simulation results indicate that the novel calibration method can accurately identify RLGs scale factor errors,drifts, misalignments errors and accelerometers drifts, and the accuracy of this method satisfy the requirements of high precision inertial navigation system.