对失效诊断的基本内容以及诊断依据进行了介绍，认为机械装备的失效规律与事物发展变化的一般性规律相同，即失效总是发生于系统的薄弱环节，并起源于构件上的应力集中部位。对机械装备的“生命历程”进行了划分，并对从原材料到产品的设计、加工、库存和运输、装配及服役等这些环节中的失效因素作了分类说明，对各环节中的主要失效形式、失效机理以及失效诊断依据等进行了归纳和总结，同时对失效预防的基本原理和程序作了介绍。结合实际分析中一些典型案例，介绍了几种不同失效形式的诊断过程和失效预防技术在机械装备安全服役中的具体应用。

The basic content and diagnosis basis of failure diagnosis are introduced. It is considered that the failure law of mechanical equipments is the same as the general law of development and change of things; that is to say, the failure always occurs at the weak part of the system and originates from the stress concentration area of the components. The life course of mechanical equipments is divided. The failure factors in the links from raw materials to design, processing, inventory, transportation, assembly and service of products are classified and described, the main failure modes, failure mechanism and failure diagnosis basis of each link are summarized, and the basic principles and procedures of failure prevention are introduced. Combined with some typical cases in practical analysis, the diagnosis process of several different failure modes and the application of failure prevention techniques in safety service of mechanical equipments are introduced.