Mechanical equipment condition monitoring and fault diagnosis techniques generally contain vibration signal, sound signal, temperature signal detection and lubricating oil analysis. Oil analysis provides a nondestructive testing diagnostic method for predicting possible impending failure and for avoiding catastrophic failures long before they occur and furthermore tends to determine the frequencies of oil changes and the remaining life of oil with the consequence of reducing maintenance costs and downtime. Oil analysis can be sorted into two categories, namely physical and chemical analysis and WDA analysis. An overview of various normal oil analysis technologies has been addressed. Some real cases resolving engineering problems with oil analysis technology are presented in this review. Fifty one various recent patents were reviewed in this paper on oil analysis technologies and the latent technology developments of oil analysis over the past decade were stated here. Those to some extent show evolution trends concerning latent oil analysis technology and expect future developments in this domain which is on-line and web-based remote intelligence oil analysis monitoring system and information fusion technology.