The pulse CO2 laser light spot is measured by the measurement of diffused reflection and infrared imaging. The mechanism of usign Uncooled IRFPA Camera with elect-scanning system to capture narrow-pulse CO2 laser is analyzed ,and the cause of half-spot-light phenomena is explained ;Furthermore ,single pulse laser beam is captured fully and stably by syn chronously triggering laser. Thus the relative intensity distribution and beam quality parameters of pulse CO2 laser we are obtained.