Abstarct: Land subsidence is one of the most destructive geological phenomena that can cause irreparable financial and life damage and damage many structures and infrastructures. One of the main causes of this phenomenon is the unnecessary harvesting of groundwater aquifers. Radar interferometric technique is a suitable method for detecting changes occurring on the surface of the Earth. The calculation of displacements occurring at the ground level using this technique has unique capabilities in terms of cost, time and accuracy compared to other measurement techniques. In this study, the amount of subsidence in Mashhad plain was calculated and determined using radar interferometry technique from 16/10/2007 to 02/06/2008 and 28/05/2015 to 24/05/2018. For this purpose, the data of two different sensors ALOS and Sentinel-1, which are in radar L and C, respectively. Cumulative maximum subsidence value calculated from ALOS satellite is 13.7 cm between 16/10/2007 to 02/06/2008 and Sentinel-1 satellite 53.8 cm between 28/05/08 / 2015 has been until 24/05/2018. Distribution of subsidence zones also indicates maximum settlement in the central part of Mashhad plain and northwest. Groundwater level of the submerged area has been steadily decreasing since 2006 and the water level in the piezometric wells has declined every year compared to the previous year. By comparing groundwater level mapping in Mashhad plain with identified wells position in the subsidence area, it is determined that the highest level of water loss is related to the subsidence area. Therefore, the subsidence occurred in a part of the plain that had the highest groundwater level decline.