In order to measure the intensity of the output power of pulsed nitrogen lasers (3371 Å), a new sensitive chemical actinometer is studied. Potassium ferrioxalate with 1 : 10 phenanthroline is used as the chemical actinometer. The average output energy of approximately 480 W per pulse has been measured. It is found that the laser output at a N2 gas pressure of 4.7 Torr seems to be most efficient. Results of a detailed investigation on relations between laser pulses and the discharge current are also reported.