Formations of active species and by-products are different from bubbling different gases in a pulsed high-voltage discharge reactor. The identification of all the products and the formation rate determination of active species are quite important as the process is applied to wastewater disposal. Serials of measurements were conducted to do the identifications and determinations in this paper. Amounts of center dot OH all increased but that of H2O2 all decreased by bubbling gas. The center dot OH formation rate was 3.49 x10(-7), 3.56 x 10(-7), 3.21 x 10(-7) and 1.94 x 10(-7) mol l(-1) s(-1) with bubbling nitrogen, argon, air and oxygen respectively, but it was 1.61 x 10(-7) mol s(-1) l(-1) without bubbling. Without any bubbling, the H2O2 formation rate was up to 6.53 x 10(-6) mol l(-1) s(-1), while it was 9.97 x 10(-7), 1.663 x 10(-7), 1.73 x 10(-6) and 3.14 x 10(-6) mol l(-1) s(-1) with bubbling nitrogen, argon, air and oxygen, respectively. NO2- and NO3- was detected in discharged water with bubbling nitrogenous gas. Their formation made the pH decreased.