The mechanical and physical characteristics have great impact on the shell shucking of walnut. Taking the shucking force as the evaluation indicator, the effects of mechanical and physical characteristics, which include the loading orientation, loading rate, moisture content and walnut partical size, on walnut shucking were investigated by means of single factor test. The results show that: 1) the loading orientation and loading rate affect the shucking force significantly, and the needed force is the minimum when the walnut is horizontally placed and loaded at the rate of 50mm/min; 2) the moisture content has significant effects on the shucking force, and with the increase of drying time, the moisture content of walnut decrease gradually, which results in the increases of the needed shucking force;3) the particle size has no great effect on the shucking force, but great difference in particle size usually corresponds to different walnut shucking force. In order to investigate the shucking technology and design the efficient sheller, it’s highly significant to study on the mechanical and physical characteristics of walnut.