Image Fusion in remote sensing has emerged as a popular protocol because it has proven useful in many areas, especially in the fields of environment, agriculture and land cover classification. Simply image fusion involves combining all relevant information from many images and then forming a single fused image. The fused image possess the characteristics of all the images used for fusion. Advantages of fusion are, it reduces the amount of data and creates an appropriate image that can be easily understood by humans and machines. This paper provides some technique on different kinds of remote sensing image fusion and also shows the advantage and disadvantage of each technique.