We constructed the three-dimensional crustal model of the front area of Sichuan-Yunnan rhombic block using the iterative forward-inversion method. The gravity anomaly data, the multi-scale wavelet decomposition method and Parker interface inversion Parker interface inversion method are used during the crustal layer modelling. The magnetic anomaly data and the three-dimensional interpretation method are used in the fault modelling. The fault models we constructed in this area are the regional large fault including Lancangjiang fault, Wuliangshan fault, Honghe fault, Ailaoshan fault, Yuanmou fault, Xiaojiang fault and Shizong fault. The results show that the depth of the bottom of the upper crust in this area is between 9 and 18 km, and its relief is mainly controlled by the main faults. The depth of the bottom of the middle crust is between 25 and 34 km, and the fault control is weakened, showing the overall rise from north to south; The depth of Moho is between 31-41km, showing the crust thinning from north to south. The depth of the model constructed in this paper has similar range and significant correlation with the depth of Crust1.0 model-the correlation coefficient are greater than 0.5 and 0.8 of bottom of the middle crust and the Moho respectively.