Application of solar energy for domestic and industrial heating purposes has been become very popular. Flat plate collector type solar water heater is one of the most widely used solar applications. The solar collector is the key component in solar energy systems. It absorbs the solar radiation and converts it into a useful form of energy that can be applied to meet a demand. Out of various types of solar collectors, the flat-plate collectors are most economical and popular, since they are fixed permanently in position, involve simple construction and require little maintenance. Flat plate solar collectors used in modern domestic hot water systems have not changed significantly in the past few years. Recently lot of research has been carried out on the improvement of the thermal efficiency of solar flat plate collector. These types of absorbers typically have high heat losses through convective and radiative heat transfer. This Project has a review on number of design investigated which explores the recent advancements and efforts made in improving the performance of the flat plate collector.