Plasma Pockels cell,which can use a thin crystal to perform the uniform electro-optical effect,is an ideal component as average-power optical switch with large aperture. With average power load,the thermal effect of the DKDP crystal is analyzed by use of finite element methods. With 5 J/10Hz laser irradiation,the depolarization loss on 3 mm thickness DKDP is 0.16％. A repetition rate plasma Pockels cell of 10 Hz with Φ20mm aperture has been fabricated. It is optimized with the limited space of repetition rate diode pumped laser. The specificationes of the plasma Pockels cell are static transition of 97.2％;switching efficiency of 99.8％,and the switch rising time of 11 ns.