The invention provides a production line layout simulation system and method based on mixed reality in order to solve technical problems of long production line layout debugging period and high investment cost in the prior art. The method includes realization steps: a to-be-simulated production line equipment three-dimensional model is established, and functions of the three-dimensional model areset; a human-machine interaction module sends a control instruction to a model processing module, an environment scanning module, a data storage module, a logic control module and a display module; the model processing module receives and optimizes the to-be-simulated production line equipment three-dimensional model; the environment scanning module scans and arranges a real workshop environment of a to-be-simulated production line and optimizes a scanning result; the data storage module stores different models; the logic control module detects a collision interference relation between the established to-be-simulated production line three-dimensional model and a real workshop environment model; and the display module displays the to-be-simulated production line three-dimensional model andthe real workshop environment. The system and method can be used for layout design of production lines.