本文提出了一种模拟“S”型曲线的较有效的方法-二次插值法。用该方法确定C值,不仅可以使理论曲线与实测样本值拟合的最好,而且寻找最佳C值的收敛速度优于0.618法和逐步搜索法。计算一次,平均相对误差为3.68％,计算二次的平均相对误差为1.85％。从而解决了“S”型曲线最佳模拟的手工计算问题. This paper presents a more effective method of simulating “S” curve - quadratic interpolation. Using this method to determine the C value, not only can make the theoretical curve fit the measured sample value the best, but also to find the best C value of the convergence rate is better than the 0.618 method and step by step search method. Calculated once, the average relative error of 3.68%, calculated the average relative error of the second was 1.85%. Thus solving the “S” curve of the best simulation of manual calculation problems.