Abstract: Conventional AVO inversion is mainly carried out for isotropic media,but the strata with fractures are actually anisotropic.Seismic inversion is a typical illposed problem.With the addition of anisotropic parameters,the nonlinear degree of seismic inversion is increased significantly,which makes it more difficult than traditional inversion.The SA-PSO algorithm is a hybrid optimization of particle swarm optimization and simulated annealing algorithm,which has the advantages of stronger global optimization ability,overcoming precocity phenomenon and not easy to fall into local minimum value.In this paper,the medium containing vertical cracks is approximated as HTI medium.Based on the HTI medium reflection coefficient equation,the objective function of anisotropic parameters is established.Anisotropic parameter inversion is realized by SA-PSO algorithm.Furthermore,the fracture related parameters and fluid factors are predicted based on the correlation between the fluid factor,fracture weakness and anisotropy parameters.The theoretical model of coal seam containing HTI type is established,and the original data are inverted by SA-PSO algorithm and PSO algorithm at the same time.The superiority of the algorithm is tested.The inversion accuracy of SA-PSO algorithm is higher and the inversion process is more stable.By adding Gaussian random noise with SNR of 5,10,20 to the data of multi layer theoretical model,the anti noise performance of the inversion method is tested.The inversion results show that the error of the inversion results is small,the inversion process can converge quickly,and the anti noise performance of the inversion is good.According to the characteristics of anisotropic parameters in the HTI type water bearing fracture,the water bearing sandstone part of Marmousi2 model is modified,and anisotropic parameters are introduced.The velocity,density and anisotropic parameter profiles are obtained through inversion,and the fluid factor prediction is realized.The inversion and prediction results are consistent with the theoretical model,which demonstrates the effectiveness of the method.