As a commonly used method by meteorologists,contour can display the distribution of meteorological elements vividly.A simple but effective automatic drawing method of objective contour for groundbased microwave radiometer data is described in this paper,which is based on the traditional tectangular grid method.This algorithm completes the contour searching from only one side and avoids smoothing,then mark the contour by a convenient method to simplify the drawing process.This automatic drawing and connection of contour is implemented in Delphi70,and two examples are given to verify this algorithm.