Nowadays, all of the iris identification methods are utilizing the strategy that extracts the feature points in the iris image firstly and then encodes these points into a certain length feature data for matching. But this strategy can make the iris identification system fragile to be attack. In order to improve the security and speed of iris identification systems, an iris identification method based on gray surface matching is proposed. This method abandons the traditional operations including the feature extracting and encoding, but uses the theory of gray surface matching based on feature analysis. Firstly, it computes the gray difference of two pixels from two different images and gets the gray difference surface. Secondly, it calculates the variance of the gray difference surface and considers this variance as the distance between two feature surfaces. At last, it decides whether these two irises are in the same eye or not according to the variance. When the distance threshold equals to 40, the accuracy is 96.89% and the speed is 53.2 ms. Experimental results demonstrate that this method has high accuracy and speed.