Ceramic discs are prepared with PZT powder doped with Sr and Mn, which is prepared through a modified Pechini process. A micro-actuator consists of two concentric rings with thickness of 0.15 mm made of PZT doped with Sr and Mn, a copper disc, on which the PZT rings are firmly mounted with organic glue, and a ceramic rod of φ2.5x100 mm stuck at the center of the disc. The top of the ceramic rod serves as pointer of the actuator. The outer PZT ring is equally divided into four quadrants separated each other, of which two vicinal parts are poled with the same direction as that of the inner PZT ring. The other two quadrants in the outer ring are poled with the opposite direction. The inner ring and the four quadrants of the outer ring are excited by three DC powers, respectively. Bending deformation of the copper disc is caused by properly regulating the excitation voltages exerted on the PZT ceramics. The position of the top of the ceramic rod varies with the bending deformation of the copper disc.