介绍了以相对失效率和相对失效概率法对串联、并联系统进行可靠度分配的基本步骤，按照此原则对１００００ｋＮ液压机主缸液压系统进行可靠度分配，并提出提高系统可靠度的措施． The basic steps of reliability distribution of series and parallel systems with relative failure rate and relative failure probability method are introduced. According to this principle, the reliability of main hydraulic system of 10000kN hydraulic machine is distributed and the measures to improve the system reliability are put forward.