Abstract: A novel linear cavity collector for trough solar thermal power generation system is proposed in this work.The effects of focal length,arc structure and opening width on the optical performance of the system are simulated by Tracepro.The thermal performance of the collector is parametrically analyzed with thermal network model.The optimized structure of the novel cavity collector is major arc type with an opening width of 70 mm,and the matched focal length is 2100 mm.The optimization results of the linear cavity collector with optimized structure show that when the direct solar radiation intensity is 500 W/m2 and the collecting temperature is 650 K,the photothermal conversion efficiency of the system can reach 65.3%.The comparative analysis with a kind of traditional vacuum tube collector shows that the novel cavity collector has better solar collecting performance than that of the UVAC Cermet vacuum tube.In addition,the production and maintenance costs of the linear cavity collector are obviously lower than that of vacuum tube collector,which is of great significance to promote trough solar thermal power generation technology.