设A、B两点坐标为(x1,y1)、(x2,y2),AB中点O'坐标为（x0,y0）,则x1+x2=2x0y1+y2=2y0(y1/x1)*(y2/x2)=-1,即y1y2=-x1x2y1^2=2px1y2^2=2px2(y1y2)^2=4p^2x1x2=-4p^2y1y2y1y2=-4p^2y1^2+y2^2=2p(x1+x2)(y1+y2)^2-2y1y2=2p...是参数方程! 不是普通方程用t把xy代下就好了啊