Abstract: Rock mass classification is an important means for engineers to identify the properties of engineering rock mass. The development of the classification methods somewhat reflects the status quo of rock engineering. The commonly used classification methods were introduced so as to elaborate on the characteristics of classification method development as follows: 1. the core factor changed from the strength of rock block to the rock mass structure and the properties of structural plane; 2. apart from the properties of rock block itself, the surrounding conditions of the rock were also covered in nowadays classification methods; 3. instead of qualitative classification, the integration of qualitative classification and quantitative classification were used in the newly developed methods. It ' s also summarized that the classification methods exhibit the following developing trends: firstly, classification methods should be developed to meet the requirements of rock engineering in deep or complex conditions. Secondly, the output information should not only include rock stability states, but also parameters and treating methods. Thirdly, domestic classification systems are disordered and inefficient, and therefore needs to be unified and subdivided. Suggestions are also given to improve the classification systems.

Key words: rock mass, quality, classification, status quo, improve