In this paper, the micro-seepage characteristics of low-permeability cores in low permeability reservoirs are analyzed, and on the basis of experimental research, the changes of starting pressure gradient under the condition of water flooding and microemulsion flooding in low permeability reservoir are compared. Based on the boundary layer properties that initiate the pressure gradient of the low permeability reservoir, the low velocity nonlinear seepage flow under the condition of microemulsion flooding in the low permeability reservoir is studied, and the corresponding non-Darcy percolation equation is established. And the accuracy of the non-Darcy percolation equation is verified by simulating the experimental results of the experimental rock samples.