Synergic effect of greenhouse vegetable wastes (GVWs) and lignite coal was investigated with different feedstock particle sizes and pyrolysis temperatures by using natural catalysts (calcite, dolomite, and zeolite) in a laboratory scale fast pyrolysis experimental system. The yields of co-pyrolysis products (biochar, bio-oil, and gases) and bio-oil composition were used in revealing the synergic effects. The study results showed that a positive synergic effect in biochar yield but negative synergic effects in biooil and gas yields were observed. The mean respective yields of biochar, bio-oil, and gas of GVWs as wt% were 41.67, 40.05, 38.96 for calcite; 29.55, 30.79, 30.88 for dolomite; and 28.79, 29.16, 30.16 for zeolite. The mean respective yields of biochar, and gas of GVWs-coal blend as wt% were 55.93, 54.16, 53.87 for calcite; 21.73, 22.93, 23.24 for dolomite; and 22.34, 22.92, 22.90 for zeolite. Catalysts had no significant influences on the pyrolysis products yields of GVWs and GVWs-coal blend compared to the control. Similarly, no significant effects of catalysts on bio-oil composition were also observed. Feedstock particle size and pyrolysis temperature had little effect on the yields of products bio-oil compositions. (C) 2018 Elsevier Ltd. All rights reserved.