Detection of unauthorized construction or illegal buildings poses a significant problem to municipal parties across the countries. Every country faces some form of problem related to unauthorized construction. In this review we presented concise summary of recent research papers. Summary includes method, technique and problem faced by authors, Table [1] include comparison of research paper on 6 different parameters that are Primary Technique used, Dataset, Algorithm Enhancement, Processing Speed, Target Object, Difference in Technique. Fig 1 shows a general process used by authors to detect unauthorized construction, Fig 2 shows percentage of how many authors used Machine learning, Deep learning and other methods in their research paper.