Simulation is the imitation of real events or methods. It is often used interchangeably with the term modeling (such as modeling in natural systems). Simulation attempts to show some characteristics of complex physical systems according to the computational model of phenomena, environments or experiments. Simulation is used to understand the operation of real systems in the real world, for example, modeling natural systems such as human body. It can also be used to simulate some technologies (such as new aircraft) or engineering concerns (such as earthquake resistance of buildings). An interactive physical instrument that simulates reality, and a "simulator" is also an integral part of simulation. For example, the space shuttle simulator is used to help astronauts understand all kinds of complicated situations related to flying the space shuttle. Short for Mathematical Simulation Test. When using mathematical model method to study complex process, after establishing mathematical model and determining model parameters, the mathematical model is solved and the calculation results of process characteristics under different conditions are obtained.

For example, when studying the operation optimization of distillation equipment, we can get the separation effect and the consumption of heating steam and cooling water through mathematical simulation, so as to determine the best operating conditions. This kind of simulation test replaces the test with actual equipment and materials, which greatly saves the time and cost of the test work. Mathematical simulation is usually carried out on an electronic computer. According to the established mathematical model, select or create a suitable model solution method, compile the corresponding calculation program, and then perform the operation under different specified conditions.