Abstract: Two non-uniform mesh grid algorithms (viz the methods based on domain decomposition technique and coordinate transformation technique) for the Lattice-Bohzmann method based on interpolation technique, with detail ed calculation process, are presented. The simulation of the two-dimensional sudden-expansion flow was carried out in the current study, and the simulated results were then compared with the results calculated with t he uniform mesh grid algorithm. At the same time, the contrast between the two methods were also conducted during the process of simulation. The advantages of the method based on domain decomposition technique are th at the flow domain can be divided flexibly and the method can be employed to structures with various shapes, while to the method based on coordinate transformation technique, a suitable curvilinear coordinate system sh ould be established, and the process of calculation is simple, highly efficient in computation.