This paper proposes a shift-register-based multichannel ultrasonic focusing delay control method using a complex programmablelogic device (CPLD) for a high resolution of ultrasonic focusing system. The proposed method can achieve the ultrasonic focusingthrough the delay control of driving signals of each ultrasonic transducer of an ultrasonic array. The delay of the driving signals of allultrasonic channels can be controlled by setting the shift register in the CPLD. The experiment verified that the frequency of the clockused for the delay control increased, the error of the focusing point decreased, and the diameter of the focusing point decreased as thelength of the shift register in the proposed method. The proposed method used only one CPLD for ultrasonic focusing and did notrequire to use complex hardware circuits. Therefore, the resources required for the design of an ultrasonic focusing system could bereduced. The proposed method can be applied to the fields of human computer interaction (HCI), virtual reality (VR) and augmentedreality (AR).