In order to guide the construction project of north Shanxi modern coal chemical industry park, and to obtain data from several aspects including output, yield, components etc. of upgraded low rank coal, coal gas, tar and waste water after pyrolyzation of low rank coal, a pilot scale experiment of cascade and clean utilization of low rank coal is carried out under different working conditions for a period of two months. Experimental results show that pyrolyzing furnace can extract more than 90% of volatile components from coal, producing oil-gas products with high added-value; yield of upgraded low rank coal decreases with the increase of pyrolysis temperature, and the yield of coal gas increases with the rising of pyrolysis temperature; under conditions that the pyrolysis temperature is 700 ℃ and pyrolysis time is 7 h, the yield of tar reaches a maximum value (6.29%); the yield of pyrolysis effluent shows no big change with the rising of pyrolysis temperature; the coal gas containing high content of CH₄ is suitable to produce synthetic natural gas.