Preionization technique is the key technology of TEA CO_2 lasers to obtain large volume uniform main discharge. The Printed Circuit Board (PCB) preionization technique utilizes a distributing capacitor coupler configuration to produce relatively strong UV preionization around cathode. The combination of appropriate preionization intensity and better uniformity make it more suitable for producing high-pulse-repetition and high average power laser.20.4 J pulse output energy is obtained from a PCB preionized TEA CO_2 laser. The experimental setup consists of two same laser modules each of which has a 5 cm×4 cm×90 cm discharge volume. The electro-optical conversion efficiency reaches 12.8%. The clearing ratio is over 3 when the laser operates at repetition rate. Average power as high as 3.6 kW is achieved at the maximum repetition rate of 180 Hz.