The universal quality characteristics of traditional equipment, such as reliability, maintainability, etc., can be characterized by the quality characteristics in a certain aspect of an equipment from different sides. In order to analyze the equipment quality, some parameters are put forward, such as Reliability, Maintainability, safety, Supportability etc. But, each of these parameters only reflects one attribute of the equipment partially. Hence a compound parameter is necessary to show the comprehensive quality attribute of the equipment during the operational process. In this study, an Equipment Operational Integrity (EOI) is put forward, and defined as the attribute existence when equipment is sound and unimpaired while providing the desired level of equipment safety, performance, durability, supportability, survivability and recoverability. Then, a quantitative measurement method is proposed, which uses Equipment Operational Integrity Degree (EOID) to measure EOI, Io=f(U,A,S,C,Su,Rc), linearly simplified as Io=UASCSuRc. And Io is evaluated based on durability degree U, availability degree A, safety degree S, livability degree C, survivability degree Su and recoverability degree Rc. Also, the Equipment Readiness Rate R can be used to express EOI, R=Eintact/Etotal, here Eintact is intact equipment amount and Etotal is total equipment amount. And the connotation of the EOI is discussed in details, which reveals that the Equipment Operational Integrity tells if the equipment is capable to operate, the Equipment Operational Suitability tells if the equipment is suitable to operate, the Equipment Operational Effectiveness tells if the equipment is effective to operate, and all of them compound the three basic attributes of equipment. Meanwhile, the durability, survivability and recoverability of equipment are explained carefully, including the concepts and measurement methods. And the interference model of equipment CapabilityLoad is presented to show the equipment failure probability due to the weak loadbearing capabilities comparing with the acting loads during equipment operating process.