Infrared image edge detection is one of the difficult problems in image processing.Based on the characteristics of infrared image,the minimum error thresholding algorithm is extended to the fuzzy domain and applied to the infrared image edge detection.The fuzzy edge detection algorithm for infrared image based on standard deviation is proposed.Firstly,a gradient operator based on local standard deviation is performed and potential edge regions are well separated.Secondly,a fuzzy minimum error thresholding algorithm is introduced to find a fuzzy thresholding of the gradient image,which partitions the gradient image into edge region and non-edge region.The experiment is conducted on various infrared images and the results show that the proposed approach has better performance than some classical edge detection methods based on gradient.