Abstract: Based on the arched structure and the characteristics of the wedge-shaped cutter intruding into the rock mass, a new pre-drilling in-situ rock mass shearing instrument suitable for in-situ rock mass shear strength measurement has been developed. By designing the overall structure of the pre-drilling in-situ rock mass shear instrument, and using finite element analysis software to simulate and analyze the key components, the simulation results show that the design of the key components is reasonable; in addition, the shear instrument is calibrated and tested. The field test was carried out on the poured concrete platform, and the test showed that the performance parameters met the design requirements and had good in-situ test performance.