In this paper, the key research is to study the integration velocity strapdown testing system which based on the MIMU (Micro Inertial Measurement Unit). The composition of the velocity strapdown system is introduced. The MIMU and testing system is designed using the methods of micromachined design, ASIC design and the system integration design. The operating principle and its structure of the MIMU is elaborated in this paper, and then the composition map of MIMU is introduced, the temperature compensation of this MIMU and the dynamic response matching range are given in this paper. Finally the testing process of testing system is elaborated carefully and the practical MIMU is fabricated.