Liquid hydrogen and oxygen are common used fuel and oxidizer in liquid rocket motor,and ultraviolet radiation is thought mostly result from the transition of OH from excited state to ground state with peak value at 281 nm and 306 nm.A 2-D model is built to calculate the spatial distribution of UV radiation intensity,and the spectral absorption coefficient is calculated based on HITRAN database.The ignition of lab-scale hydrogen oxygen rocket motor is performed.Ultraviolet spectral and spatial radiation of the rocket plume are measured.The model is validated by experiment data.This research can be used in optimization of ultraviolet approach warning system and evaluation of system detection performance.