Based on the abundant field investigation and statistical data, some different types of classification methods for rock mass quality are used in this paper to evaluate the rock mass quality of a hydroelectric station area on the Jinsha River.Finally, combine with the Qualitative evaluation of the scene and analyzing those results, a reasonable and science achievement is obtained.Based on evaluation results, elaborated on the effect of columnar jointed to rock mass quality on dam site, that the columnar joints basalts is a special kind of rock structure, the dam of columnar jointed basalt rock mass quality classification of the indicators should be integrated different from the non-columnar jointed basalt, columnar jointed basalts that should considerate focus on the mechanical integrity, rather than non-columna jointed basalt account into not only the mechanical integrity but also the geometric integrity should be considered, these make the necessary foundation for further study of rock mass classification methods and parameter selection.