According to the fact of connectors’ large numbers and various types in system, study influence of connectors to reliability of system. Combine typical connection modes, reasoning in theory, proved influence of connectors to reliability of system cannot be ignore. From the point of view of connectors as parts of function assemblies of system, analyzed the influence of connectors to reliability of system, and educed the basic consult of optimized connection manners. The research indicated that course of design and selection determined the academic reliability of system, and in application of project, reliability of system can be manage from analyzing the function series-wound points of system and draw attention to credibility of system.