Objective To investigate tumor-induced angiogenesis influenced by the mechanical environments in and out of tumor, and simulate the capillary network numerically.Methods Considering the effects of both endothelia cell(EC) and extra cellular matrix(ECM), it is assumed that ECM to be linear visco-elastic.The displacement of ECM is obtained from force balance equation consisted of EC traction, ECM visco-elastic force and external force.The capillary network in and out of tumor is simulated numerically by discrete equation of EC movement equation.Results Taking account of the influence from the mechanical environment, a relatively realistic capillary network could be obtained.The mechanical factor resulted in a layered structure:at the edge of tumor, numerous capillaries are generated, while the closer to the tumor center, less capillaries there would be.Conclusion Generated by such computer simulations, this theoretical capillary networks correspond with realistic physiology and provide a premise for further research.