To solve the problem of evaluating profile error of surface, theoretical surface was built by interpolating design points at the method of bicubic Non-Uniform Rational B-Spline(NURBS). Measuring points were gained by laser measurement, and the mathematical model was built for computing the error. The particle swarm optimization (PSO) was applied to compute the minimum distance from measuring points to design surface, which can evaluate profile error of surface accurately. At the same time, MATLAB software was used to realize visualization of profile error evaluation of free-form surface. Experiments show that the proposed optimization can obtain precise result, the method is feasible, visualization makes geometric feature observed more intuitive and there is important practical significance.