The invention relates to the technical field of environmental science, and discloses an analogue
simulation method and
system for large-scale gas
diffusion. The method comprises the following steps: determining a
simulation purpose and collecting related data, constructing a geometric model of a
simulation area, carrying out multi-scale grid division, estimating a gas
diffusion path, speed and concentration through preliminary simulation, then correcting an
estimation result and selecting a proper
physical model, and using a multi-scale
coupling strategy to simulate the gas
diffusion path, speed and concentration. The method comprises the following steps: carrying out
coupling modeling on physical models of different scales, designing a
parallel algorithm to simulate a multi-scale
coupling model, evaluating a simulation result and analyzing an error in combination with actually measured data, carrying out optimization, analyzing the simulation result and evaluating an
environmental risk, and displaying a gas diffusion process through three-dimensional
visualization. According to the method, the simulation precision, the environmental adaptability and the response flexibility are improved, and precise simulation and
risk assessment of large-scale gas diffusion in a complex environment are realized.