Satellite images are unclear and it is very difficult to get information from them. This paper deals with the detection of edges of a satellite image. Here, edge detection is the fundamental tool of image segmentation. Image segmentation is a process of dividing an digital image into set of pixels, it is used to identify the objects and boundaries un an image.A set of connected pixels which forms boundary between two disjoint regions defines an edge,which is very important to acquire information from an image.There are many segmentation techniques like threshold, clustering, PDE, ANN based techniques, of all these methods edge based technique is the most optimum one. Canny edge detection algorithm is used to detect a wide range of edges in image uses multi-stage algorithm. Low error rate,good localization and single response are the main features of this algorithm.