Abstract: A lot of data obtained from laboratory test and spot test are analyzed, by applying the theory of the fault process in a maintainable system. The life distribution rules of the reliability data for submersible motor-pump have been presented and proved. The failure distribution of submersible motor-pumps accords with Weibull distribution in their whole life. The fail-ures belong to early failures when the use time of submersible motor-pumps is less than 600 h. The failures remain with ran-dom failures when the use time is more than 600 h but is less than 3 200 h. And the failures belong to wear-out-failures when the use time is more than 3 200 h. If the submersible mo-tor-pump is fully milled, the failure can be analyzed with ex-ponential distribution, or it should be analyzed with Weibull distribution. The test results show that the primary measure-ments that quality of submersible motor-pump is improved are to improve the quality of mechanical seal sets and safeguards. At the same time, the search shows practical value in reliability assessment and reliability design.

Key words: Failure distribution, Submersible motor-pump, Test