The invention discloses a grid-free lattice Boltzmann method based on semi-Lagrangian and a radial basis function, and belongs to the field of computational fluid mechanics, which enables the latticeBoltzmann method (LBM) to get rid of the limitation of uniform grids by introducing a semi-Lagrangian method and a radial basis function interpolation method, and further expands the application of the LBM in complex flow problems. The method comprises the following steps: firstly, introducing an SL method into a lattice Boltzmann method, and finding a migration starting point, namely x-e Alpha Delta t, obtaining a distribution function of a starting point (x-e Alpha Delta t) by introducing a local RBF interpolation method; According to the local RBF interpolation method, (a relation is shownin the description), wherein phi (x) is a target position function value, Phi (|| x-xi ||) is a radial basis function, and | | x-xi|| is a Euclidean norm, p (x) is a multivariate polynomial, n is thenumber of supporting points, m is the order of the multivariate polynomial, and m is an interpolation coefficient.