Abstract: In view of the importance of the liquid and plastic limit moisture content experiment of fine-grained soil in the teaching of soil mechanics, and the limitation of repeated test classroom experiments, the virtual experiment design and development is carried out based on Unity3D platform to realize the virtual experiment of the liquid and plastic limit moisture content experiment for random test samples. The virtual experiment of liquid plastic limit moisture content can realistically simulate the three-dimensional scene of the laboratory, equipment and operation process and can enhance the sense of reality of the experimental experience. With random combination of multi parameters of test samples, random test samples are generated to avoid the repeatability of experimental results. And the human-computer interaction design in the experimental operation process can realize the assessment of theoretical knowledge and experimental points, and improve the auxiliary teaching function of virtual experiments.