Abstract:A BKHP-12 mixing vehicle’s sub-frame which is used in hydraulic fracture is studied in this paper. The sub-frame’s structure and load are simplified firstly, and the finite element model of the sub-frame is established, then the performance is analysed by finite element software ANSYS. The weakness of sub-frame is found out, the rationality of the structure is tested and the improvement measures is put forward which is based on the static analysis in bending and torsion condition. The sub-frame’s modality is analysed under the constraint conditions, and its vibration characteristics are also analyzed. The results show that the sub-frame has good vibration resistance characteristics of external excitation. The research method in this paper has directive value to develop mixing vehicle for hydraulic fracturing.