Abstract: This article presented a grey association analysis method to evaluate and select bits,through comparing and analyses methods of select bits in current.The method mentioned above can be not only appreciated for attentions of deportment to macro analysis the bit used,but can be a guiding of selecting bits in some structure or well,and the number of evaluating factors associated with bit use can be changed freely in the model.Through the analysis of drilling information in Chuan Zhong oil field,the method is of the application,prospects,helpful for bits selection and decreasing drilling cost.