Abstract: Straw was mixed with 2 different coals including Neimeng lignite and Shenfu bituminous coal in different proportions of 0∶100, 20∶80, 40∶60, 60∶40, 80∶20, and 100∶0. The co-pyrolysis experiments of the blends were conducted in a fixed bed reactor. The co-pyrolysis characteristic of straw and coal blends and synergetic effects during co-pyrolysis were studied. The results show that the yield of co-pyrolysis of straw and coal blend based on volatile matters were higher than those of the sum of straw and coal individually. Meanwhile, considerable deviations from the average weighted value of gas yield were detected, especially for straw and Shenfu bituminous coal blend. The more straw was added into blend, the more gas yield produced during co-pyrolysis. However, straw addition did not play significant role in the char yield and organic functional groups characterization.