Carbon fiber reinforced plastic (CFRP) composites have been widely used in many applications due to their superior properties of high strength-weight ratio, high stiffness, and high wear resistance. For assembly purposes, hole making is necessary for different applications of CFRP composites. Rotary ultrasonic machining (RUM) has been proposed and investigated for hole making of CFRP composites. Studies on the effects of machining variables, tool variables, workpiece orientation, and cooling conditions on output variables in RUM of CFRP composites have been investigated. The carbon fiber reinforcement structures of CFRP composites also affect the machining performances and part's quality. However, there is no reported investigation on studying carbon fiber reinforcement structures' influences in RUM of CFRP composites. Experiments were conducted for this paper to investigate the effects of carbon fiber reinforcement structure on cutting force, torque, and surface roughness. Three major conclusions can be drawn from the results of this experimental investigation. First, CFRP composites with unidirectional structure led to the smallest cutting force and torque, followed by CFRP composites with plain woven structure and twill woven structure. Second, the surface roughness on CFRP composites with plain woven structure was the smallest, followed by the CFRP composites with unidirectional structure and twill woven structure. In addition, CFRP composites with different reinforcement structures have the same tendencies of output variables with different machining variables.