根据非球面生产的实际情况．指出非球面最适球面的确定方法．详细分析最适球面的计算方法．并对一抛物面进行了实例计算，通过与最小二乘法的计算结果比较．指出该方法具有计算简单、与加工工艺过程相符合等特点。

Based on the condition of aspheric production, the method how to get the aspheric reference sphere is presented in this paper. The calculating method of the reference sphere is analyzed in detail, by calculating the reference sphere of a paraboloid and comparing it with the result of the least square method.The tri-point method has a merit of simple calculation and it is adapted to the process of the craft.