Virtual simulation of surveying instruments is a specific aspect of virtual measurement that combines three technologies: three-dimensional (3D) modeling, virtual simulation, and computer technology. In order to solve problems such as instrument damage, shortage of practical instruments for students, and difficulties in practical training, this paper takes the level instrument in surveying instruments as an example, and uses virtual reality simulation technology, Unity3D technology, 3ds Max modeling technology, and related computer technologies to build a virtual simulation of the level instrument. The research mainly focuses on the following aspects: (1) Using 3ds Max software, the tripod model was established, and the telescope model, objective lens model, spiral model, and base model of the level instrument were also established, and then combined into a complete level instrument. Finally, the tripod model and the level instrument model were imported into Unity3D for assembly and use. (2) Using C# programming language, SQL Server database, and Unity3D, a virtual terrain was built to simulate the cognitive simulation of the level instrument, the principle of centering and leveling simulation, and the principle of height measurement simulation. (3) The cognitive simulation of the level instrument was carried out in the Unity3D-based surveying instrument cognitive simulation system; the simulation of the principle of level instrument height measurement was also performed. Through the reading of the level staff, the elevation was calculated. This virtual simulation system can be used for classroom teaching demonstrations and student experiments, effectively reducing the damage of expensive surveying instruments, easing equipment shortages, and improving teaching effectiveness.