Abstract: The low start-up pressure gradient and serious anisotropy have made the fact that effect of fracture parameters on productivity in fractured horizontal wells in ultra-low permeability reservoir is quite different from that in traditional reservoir. According to low permeability and ultra-low permeability reservoir characteristics, the influence of fracture parameters on fractured horizontal well productivity under different permeability heterogeneity and different pressure gradient conditions are analyzed respectively using numerical simulation method. The results show that in those kinds of reservoirs with weak heterogeneity, the fracturing horizontal well production conditions are similar to that in the case of homogeneous reservoir. On the other hand, when the reservoir heterogeneity is strong, it is suggested to select larger number of fractures and longer fracture half-length for production rather than in homogeneous reservoir; In the case of larger start- up pressure gradient, selecting larger number of fractures for production is proposed.