A directional well-drilling diamond drill bit comprises a drill bit body and further comprises fixed cutter wings, roller cones, a hydraulic structure and the like which are arranged on the drill bitbody. The fixed cutter wings are provided with cutting teeth. The roller cones are provided with teeth. The directional well-drilling diamond drill bit is characterized in that one or more of the fixed cutter wings are provided with one or more grooves, the roller cones are arranged in the grooves, and the roller cones and the fixed cutter wings are in rotating connection. According to the directional well-drilling diamond drill bit, the torque of the drill bit is reduced through the roller cones, the working safety of the drill bit is improved while the stability of the working face of the drill bit is improved, the situation that moving parts fall down at a well bottom is reduced or even avoided, and the available space of a drill bit cutting structure and the hydraulic structure is enlarged.