In this study, we estimate Bouguer anomaly using local gravity data for North-West of Iran. We combine this anomaly with seismic data to constraint a 2D model for density variation of crust in this region. We used receiver function results of 23 seismic stations of IASBS and gravity data 79 station of National Cartography Center (NCC). The data was collected along east-west profile from Caspian Sea to Uremia Lake. According to our model, the thinning of crust close to the Caspian Sea can causes positive Bouguer anomaly. There is no underplating beneath the Talesh Mountain in our model. Also the buried mass under the Sahand volcano mountain has less depth than the Sabalan volcano. The mass distribution creating the negative anomaly under the Sahand and Sabalan Mountains has same width and both of them start from shallow depth underground and continue to the west hillside. Although, our result revealed existence of a thick sedimentary layer in east of Sahand mountain about latitude of 47°, it is hard to obtain the width, depth and density of buried mass distribution causing this negative anomaly.