Using the observation data after China Earthquake Network’s digitization (2008-2012), we contrasted and analyzed body wave magnitude between CENC and NEIC from magnitude size, distance, depth and azimuth. The compare results show that, after digitization, short-period P-wave magnitude m_b determined by CENC and NEIC has no systematic difference, but broadband body-wave magnitude m_B determined by CENC is quite different from short-period P-wave magnitude m_b determined by NEIC (m_B determined by CENC is grater by 0.22); hypocenter depth has some influence on magnitude deviation which shallow earthquake is bigger than deep earthquake; whereas distance and azimuth has little influence on magnitude deviation.