A linear piezoelectric actuator is designed and fabricated based on the first longitudinal vibration and the second bending vibration mode of the rectangular block piezoelectric ceramics. The piezoelectric actuator has the feature that two alumina contacts arranged at two ends of the rectangular block piezoelectric ceramics work alternately, which improves the vibration utilization of the rectangular block piezoelectric ceramic. The finite element method is used to design the size of rectangular piezoelectric ceramics. Experiments show that the maximum noload speed of the actuator is 250 mm/s, and the maximum output force is 16 N at the voltage of 600 V. The spring heating problem of the actuator is discussed and analyzed. It was found that the spring’s resonant frequency should keep as far as possible from the working frequency of the actuator, otherwise it will make spring heating, reduce the actuator's lifespan, or damage internal structure of the actuator.