In order to let a pressfit curve accurately reflects the pressure and displacement relationship in each stage of the wheelset pressfit process,the acquisition and processing methods of the pressfit data were studied.The defects of moving average method which was used at present were pointed out and a polynomial fitting method by which smooth curves could be achieved was put forward.Based on the principle of railway standard and spline interpolation,a cubic spline interpolation method was proposed to smooth curves and process the press data.Through joint programming and simulation of VC++ and MATLAB,the curve deviations before and after using cubic spline interpolation were analyzed.It verified the feasibility and effectiveness of the cubic spline interpolation in wheelset press curve processing.