Abstract：Technical improvement has been made to existing laminar shear model box. The main idea of the technical improvement is using shafting bearing and the rigid restriction system in one side to replace ball bearing and lateral rigidity restriction system which are normally used respectively. The way of the technical improvement is changing laminar square steel frame into the one with H-formed steel and square steel stacking alternately. External diameter of the interlaminar shafting bearing has been changed from 16 mm to 72 mm，the force mechanism of the model box has been changed from “drawer” to “stack”，and the lateral rigidity restriction system has been replaced by riveted elastic thin steel plate in non-main vibration direction. The software ANSYS has been used to verify the effect of the riveted elastic thin steel plate on the dynamic characters of model box and soil. It is shown that there is a little effect on model box riveted by thin steel plate. After improvement the deadweight of the model box decreases，the interlaminar spacing is smaller than before and also can be adjusted to the needed sizes，and the force mechanism of the model box is more close to the actual one of soil. Equipment can be reused，and its operation capability is better than before. By using the improved test equipment，it can be achieved to simulate the soil performance under dynamic load.
