Summry form only given. The chemical reaction in the reactor using pulsed streamer discharges brings the improvement of the treatment efficiency and new applications. Then, the shorter pulse permits higher electric field which is applied on discharge space and causes higher efficiency of treatment. Although investigations of the reactor configuration are important, the optimization of the configuration is delicate in the case of pulsed power. When the shorter pulse drives the reactors, the issues such as matching mid diagnostics would appear as well. A developed nanosecond pulsed power generator is used to drive the chemical reactors. There are two applications of production of ozone and treatment of nitrogen oxides. In these two applications, a same coaxial reactor consisting of a wire and a cylinder is used basically but the number of the reactors connected in parallel is changed. The high efficiencies of ozone production and NOx treatment are measured respectively. The system efficiency of ozone production, including pulse power generation, is approximately 200 g/kWh. Besides, it found that the small changes of the transmission line and the connection between the transmission line and the reactor affect the efficiencies as well as the configuration of reactors. In the measurement, the use of a resistive divider deteriorated the efficiencies. In using short pulse as nanosecond pulse width, the technique to control pulsed power becomes significant. The intimate experimental results will be presented.