In order to study the walnut-cracking broken mechanism and performance of walnut-cracking device, the cracking experimental research for certain physical characteristics was done by using a walnut-cracking device based on extrusion friction mechanism. On this basic, walnut varieties, size (length of edge), the moisture content of walnut shell ,which were investigated by single-factor experiments, were tested to specify the effects of walnut cracking. The result is that the optimal scope of walnut and machine was as follows: 6°as cone basket angle of device, edge length above 28mm, thickness of the shell below 2mm and 8%~10% as moisture content of walnut.