Abstract: Perforation well fracture extension is a key factor to the success or failure of hydraulic fracture, this study combines with the rock mechanics, percolation mechanics and elastic-plastic mechanics, establish hydraulic fracture extension mechanical model of low permeability reservoir perforation layer. The numerical analysis method is adopted on the basis of considering fluid-structure interaction and dynamic effect, then the hydraulic fracture extension form of perforation layer can be acquired. The influence of perforation parameters on crack width and length are given under the condition of calculation, it analyze the influence of perforation parameters on crack propagation and provides fundamental basis for hydraulic crack propagation.