The invention provides an automobile intelligent fault diagnosis and maintenance auxiliary method and system combining subjective and objective information and a cloud model. The method comprises steps of acquiring automobile objective original diagnosis data through an OBD diagnosis port; carrying out preprocessing on the data, judging whether fault codes are in the preprocessed data, and if yes, analyzing the fault codes and providing automobile maintenance assistance; if no, carrying out quantitative conversion on acquired automobile subjective uncertainty fault sign qualitative value through a cloud model method, and comparing the qualitative value with a standard value in an automobile system standard database, wherein the system automatically diagnoses automobile fault parts initially; diagnosing the automobile fault reason through a case-based reasoning method based on a normal cloud mode; and using the rule-based reasoning to finish diagnosis and elimination of automobile faults. According to the invention, automobile faults caused by a complex condition that an automobile has a fault without a fault code or by damage of non-electronic elements are solved; automobile fault diagnosis can be highly efficiently and rapidly finished; maintenance steps are normalized; and maintenance price is properly set.