Abstract: The screw pile is a new kind of casting concrete pile which is of screw pitch on pile body.According to theoretical analysis and testing research,if the screw pitch is short,when loaded,screw thread moves with soil around it,similar to multistage expanding pile.When the bearing capacity of screw pile reaches to the ultimate load,it will be broken through the cylndrical surface out of pile,and the bearing capacity is sum of shear resistance between soil and screw threads and end resistance.Several calculation methods of bearing capacity of screw pile were introduced and also the merits and demerits of the calculation methods were analyzed too.In order to supply simple and convenient calculating method,based on the traditional calculation method,a new calculation method of screw pile bearing capacity was proposed and the factor of equivalent shaft resistance on screw piles to shaft resistance of bored pile in dry operation was analyzed and calculated theoretically,the calculating factor was put forward for engineering design.