Abstract: The differential equations of pressure for two moving surfaces hydrodynamic sliding bearing are deduced by transforming coordinate transformation method, and the concept of effective velocity is introduced. Then a simple and convenient method for engineering design of this bearing is presented. In case that other parameters keeping constant, improving effective velocity is an efficiency way to improve the bearing capacity of two moving surfaces hydrodynamic sliding bearing. As for two moving surfaces hydrodynamic sliding thrust bearing,carefully composing the directions of wedge and rotating direction of two moving surfaces is the key to improve the effective velocity.