Low speed high torque hydraulic motor is widely used in construction field for it’s excellent low speed stability which means it can directly drive load without reducing mechanism. But these motors can’t be applied to the limited radial space for it’s cylinders are evenly arranged circumferentially. A liner type hydraulic motor was designed on the base of inner curved radial piston hydraulic motor.The hydraulic cylinders of the new type motor were in the straight line by which the utilization of the axial space was improved and different out power could be gotten by changing the number of cylinders.The structure and working principle of the liner type hydraulic motor were briefly introduced.ANSYS software was used for finite element analysis. The results show that the design completely meets the design requirements of motor.