In this paper, research progress of out of autoclave(OOA) composite technology for low porosity composite was reviewed. We presented the influence of OOA materials properties including prepreg, resin and reinforcements on porosity of OOA composite, then, phenomena that affect porosity during curing were analyzed.Afterward, the relationships between porosity of OOA composite and manufacturing process conditions and parameters were also described. Finally, some suggestions on reducing porosity of OOA composite were proposed.