As a dedicated solar radio interferometer, the MingantU SpEctral RadioHeliograph (MUSER) generates massive observational data in the frequency range from 400 MHz to 15 GHz. The image quality depends strongly on the phase calibration and imaging algorithms. And, clean, which are really extraordinarily time consumption deconvolution operations, is an essential step to get high-quality images. In this paper, we proposed an approach to estimate the probably brightness of the solar disk and sky, which can give the parameters for phase calibration. Meanwhile, the number of iterations for clean algorithms can be determined by the estimated sky brightness, which can effectively improve the efficiency of clean performance. The preliminary experimental result of the MUSER imaging proves the availability of this approach.