In this study, Markov-Chain Monte Carlo algorithm is applied on group velocities of Rayleigh wave to image the density variation and shear velocity structure of the crust in Makran subduction zone. Based on previous studies, surface wave dispersion measurements are primarily sensitive to seismic shear wave velocities. In next step gravity data inversion was applied with a priori information based on surface wave analysis results to obtain Moho depth variation and crustal density structure. The reason for using gravity data set, is that surface wave group velocities are sensitive to velocity variation and have a weak density sensitivity, whereas gravity anomaly is sensitive to depth variation of discontinuities and have a good density resolution. Our results show that the Moho depth across the Makran subduction zone is increasing from the Oman seafloor and Makran forearc setting to the volcanic arc. The maximum crustal thickness in the Makran region reaches to 45- 50 km below the Taftan-Bazman volcanic arc. The Minab fault have been clearly shown in the results, as the boundary between the thick continental crust of the Arabian plate and the thin oceanic crust of the Oman Sea in the western edge of the Makran subduction zone as well. Our results show clearly that the high-velocity and density slab of the Arabian plate subducts northwards beneath the low-velocity and density in Makran.