椭圆面积公式S=πab,其中π为圆周率,a、b分别是椭圆半短轴、半长轴的长.关于椭圆面积公式的证法有多种,文献[1]利用仿射变换与仿射不变量推导出椭圆面积公式,文献[2]通过对单位正方形的拉伸(压缩)变换前后面积关系的讨论,给出了椭圆面积公式的又一证法.文献[3]利用初等数学的方法,推导出椭圆面积的计算公式.本文利用投影和定积分知识相结合的方法,给出了任意曲边形面积公式,进而给出椭圆面积公式的一种新的证法. Elliptic area formula S = πab, where π is the pi, a, b are the elliptical semi-minor axis, the length of the semi-major axis. There are a variety of methods for the elliptic area formula, literature [1] using affine transformation and affine The invariant deduces the elliptic area formula, literature [2] through the unit square stretch (compression) before and after the transformation of the relationship between the area, the elliptic area formula is another card method. [3] The use of elementary mathematics , The formula of elliptic area is deduced.The paper uses the combination of projection and definite integral knowledge to give an arbitrary curved edge area formula, and then gives a new proof of elliptic area formula.