Abstract: Synthetic aperture radar is an effective earth observation technique for areas with frequent cloud and mist cover, rain and snow perennially. But in some complex terrain areas, such as west China, there are a lot of mountains and canyons. Because of large terrain relief and complex geomorphic types, the SAR images acquired from these areas present serious geometric distortions. For example, foreshortening, layover and shadow, are usually extremely severe. The radiometric distortion induced by topographic relief is also strong. These factors limit the application of SAR mapping. In order to cope with these shortcomings, a new method and technical flow based on multi-direction and multi-polarization SAR data fusion is proposed according to complex terrain and inherent characteristics of SAR images. And corresponding software module is developed based on an independently developed software system-SAR mapping workstation. This method fuses SAR images acquired from different looking directions, with different resolutions and multi-polarization to make color orthophoto map. Firstly, it uses the target decomposition to make color images based on the multi-polarization SAR data. The color images are ortho-rectified using the range-doppler model with sparse ground control points. And the radiometric distortions induced by topography relief of the color images are eliminated using high-precision DEM. Then the SAR data of high resolution and single polarization is merged with a multi-polarized SAR data with lower resolution and acquired from the same direction based on the IHS transformation. Finally a fusion method is proposed based on slope and aspect to fuse data with opposite viewing directions in order to compensate the information in layover and shadow areas. A data fusion test is carried out using TerraSAR-X data with 3m resolution and single polarization and fully polarized RadarSAT-2 data with 8m resolution in Hengduan Mountain to make the color orthophoto map. The experiment result proves that this method is effective and practical. At present, the proposed method, technical flow and software module has been widely used in the 1:50000 Scale Topographic Mapping Project in West China.