Aiming at the great discrepancy of the joint design for cement concrete slab in port area in China and abroad,we compare the similarities and differences of joint types,spacing and load transfer mechanism between Chinese and American codes,analyze the effects of temperature,subgrade stiffness and loads on the joint through investigation and finite element calculation,and propose the method combining the limitation of the ratio of slab length and radius of relative stiffness and the analysis of tension stress to determine the joint spacing.The results show that there should be less or no expansion joints in the cement concrete slab,and all joints should be provided with dowel bars to transfer load better.