Based on the finite volume modular, the coefficient of convective heat transfer is studied, when plasma electrodes Pockels′ cell is operated at conventional pulse mode. Considering requirement of thermodynamics, the discharge cavity is redesigned to enhance convective heat transfer. The results indicate: at conventional mode, the coefficient of convective heat transfer is too small, 1.01 W/(m2·K), because of low operation pressure, low pumping speed, no considering of thermodynamics requirement. By pushing the pumping speed, increasing operating pressure, augmenting pipe diameter, and redesigning arrangement of inlets and outlets, coefficient of convective heat transfer is enhanced prominently, which reaches to 8.02 W/(m2·K).