In order to accurately measure the mushroom head wear of the bottom friction pair of the gravitational gate,the simulated friction and wear test of the mushroom head was carried out by friction and wear tester.The surface contour of the worn specimen was measured by a dial gauge,the threedimensional contour data of the surface was obtained,and the surface contour map was constructed accordingly.The surface wear volume was calculated by using the microelement model and the fitting model.The microelement method is to take the step size of the dial gauge as the micro element,calculate the wear volume of each micro element,and then add up the wear amount of spherical micro element to get the spherical wear volume.The fitting method is to convert the measured spherical data into the data in the Cartesian coordinates,and then fit the data in the coordinate system to get the fitting function,and then integrate the fitting function to get the spherical volume.The spherical volume difference before and after wear test is the spherical wear volume.The results show that compared with the weighing method,the error of micro element method and fitting method are 4.66% and 4.03% respectively,which meet the requirements of engineering measurement,and provide a more accurate method the measurement and calculation of spherical wear.