A method for calculating fractal dimension of three-dimensional rough surface based on wavelet transform was proposed. In this method,wavelet transform was used to decompose the three-dimensional surface topography data in multi- scale,and the mean value of the square of the wavelet coefficients under different decomposition scales was fitted by func- tion,then the three-dimensional fractal dimension of the rough surface was obtained. In order to verify the correctness and accuracy of the proposed method,a three-dimensional fractal surface was constructed with known parameters and the results of fractal dimension calculation under different methods were compared and analyzed. The results show that compared with the original box dimension method and the difference box dimension method,the fractal dimension error calculated by the wavelet transform method is smaller. Especially when sym4 wavelet basis function is selected in the process of wavelet transform,the calculation error of fractal dimension is the smallest,and the error can be controlled within 2%. The method was applied to calculate the fractal dimension of grinding surface. The fractal dimension of grinding surface under different roughness was obtained,which verified the practicability of the method. The method presented can calculate the fractal dimension of three-dimensional rough surface more accurately,which provides a parameter basis for the construction of fractal contact model of rough surface