Improving the light-soaking stability of silicon-based thin film solar cells is a very important issue for industrial production. In order to obtain high-efficiency a-Si:H/μc-Si:H tandem solar cells with good light-soaking stability, In this paper we first present the results about a-Si:H top solar cell with high light-soaking stability. Then we mainly investigate the influences of N/P tunnel junction and silane concentration (SC) profiling of μc-Si:H i-layer on the light-soaking stability of a-Si:H/μc-Si:H tandem solar cells. Up to now we have been able to obtain a-Si:H/μc-Si:H tandem solar cell with a light-soaking degradation ratio of only 7%.