Abstract: Points on field equipment maintenance rating are presented and basic principles on rating establishment for oil and & pipeline equipment are put forward, including consistence principle of accessories, sameness principle of working procedures, homophyly principle of operation elements, universality principle of maintenance operation factors and orderliness principle of variations.Expatiation is given on methods for setting up time rating standard, machining criterion, typical rating standard and their applications separately, and concrete steps for constituting the standards combined with substantial instances are explained.