Abstract: Three interpolating surface algorithms, i.e. bilinear, biquadratic and circular spline function radial parabolic algorithms,are provided in this programming system. The last of them is considered to be the most ideal one for interpolating surface because it has high accuracy,truly expresses the distorted flow field,and overcomes the unsmoothed joints of the biquadratic algorithm. In order to determine the intersection points between contour and network,rectangular grids of polar coordinates instead of rectangular coordinates are used. In result, many advantages for engine inlet flow field plotting can thus be achieved. This programming system can save computer time and reduce costs.