The reamer is a necessary drilling tool for directional drilling. In order to adapt to different formations, the structure of the reamer is also different. Currently, there are mainly squeeze-expanded, cut-expanded, and rock reamers. Rock reamer includes cone reamer and hob reamer. Generally, cone reamers are used in soft rock formations and hard rock formations, while hob-type reamers are used to deal with harder rocks. It is an effective way to improve the construction efficiency to select the suitable air in the construction according to the characteristics of the bottom layer.