Abstract: In order to solve the problems of high tar content of gas at the outlet of Lurgi furnace and low gasification efficiency, which hinder the clean utilization of pyrolysis products, and cause high cost of water treatment in the post-system. To reduce the yield of tar, increase gas output and coal conversion rate, Shengli lignite was used as the research object, the binary composite catalytic pyrolysis experiment of Shengli lignite was carried out in a fixed bed atmospheric pyrolysis reactor and at 600 ℃, the effects of the type and ration of binary composite catalysts prepared by four single component catalysts, K2CO3、Ca (NO3)2,CaO and Fe (NO3)3, on the pyrolysis product yield and pyrolysis conversion were investigated to reveal the catalytic pyrolysis characteristics of Shengli lignite at medium temperature. The results showed that the gas yield increased most significantly when adding 5% K/Ca catalyst with 1:1 ratio, from 8.46% without catalyst to 14.88% , and the yield of outstanding realization as H2 and CO improved very well. The tar yield decreased 62.4% compared with the pyrolysis of raw coal, in which asphaltene decreased 82.09% and aromatic hydrocarbon increased 21.69%, this shows that the addition of catalyst can reduce the yield of tar, improve the quality of gas and realize the directional conversion of pyrolysis products.