Abstract: In order to facilitate the personnel to observe the working process of the rotary steering tool, verify the steering ability of the rotary steering tool during real drilling, and guide the improvement of the build-up rate of bottom-hole assembly (BHA), the virtual reality technology is used to simulate the working process of the reduced scale rotary steering drilling experimental device. Based on the excellent 3D rendering characteristics of Unity3D, Unity3D was selected as the virtual engine platform and C# as the scripting language of the simulation system. Based on the characteristics of multi-threaded tasks of Unity3D script, a management module, which managed the script of multi-threaded task, was designed. The technologically mature NHibernate was selected as the object relational mapping framework of store data. Two methods were designed to generate the trajectory by using Mesh grid technology. The simulation system of reduced scale rotary steering drilling experimental device was developed. The system completely shows the working process of the rotary steering tool in the rock stratum, and has the function of verifying the steering ability of the rotary steering tool during real drilling, so as to guide and improve the BHA.