In order to solve edge direction positioning is not accurate and it only interpolate in one side along the edge points without considering the edge inside and outside for the traditional edge interpolation method in the process of rebuilding the image super-resolution,a novel algorithm is proposed based on the edge of binary image to determine the edge direction.It get a more reliable results by determining the edge direction with the relationship between edge pixels,and determining the interpolation side by adding variance,taking the characteristics of determining the edges into account,interpolating on one side of the edge selectively.The experiment results show that the two kinds of improved can get better effect of image reconstruction relative to the traditional edge interpolation method.