Until now, a diversity of complement inhibitors has been described, including natural proteins in the complement system and those developed by biotechnology. Complement factor I (CFI), complement factor H (CFH), C4 binding protein (C4BP), decay-accelerating factor (DAF), CD35 (CR1), membrane cofactor protein (MCP), etc., are natural inhibitors regulating complement pathways in different ways. Several complement inhibitors have been approved by Food and Drug Administration (FDA) for the treatment of related diseases, including anti-C5 monoclonal antibody, and C1 esterase inhibitor.