Qlab (Quantum Optical Simulation Laboratory) is a 3D virtual simulation software for the teaching of quantum optics. Qlab models 1:1 3D physical objects of the experimental instrument, and incorporates the corresponding physical principle algorithm. The state of the device in the optical path can realize real-time dynamic feedback, and the output is close to the real experimental data. The design of Qlab restores the ultra-clean experimental environment, and introduces noise such as environment light and detector dark count, which reflects the sensitivity of quantum optics experiments to noise and is close to the real experimental environment. Qlab is equipped with detailed teaching plans, handouts and quizzes, and integrates vivid teaching materials such as quantum entanglement principle demonstration animations in the software to provide support for teaching.