Combining the judgment document network, trial information network and random investigation of litigants, this paper uses big data analysis technology to effectively screen and rank law firms from the perspective of their scale. Shi Jing Law Firm, Yingke Law Firm, Dacheng Law Firm, Deheng Law Firm, Wen Zhong Law Firm, Tianchi Juntai Law Firm and Zhonglun Law Firm.