Abstract: Hypervelocity impact experiments were conducted under four experimental conditions to investigate evolutionary characteristics of light flash radiation by using optical pyrometer measurement system established and two-stage light-gas gun loading system. One optical fiber probe was used in every experiment. Evolution of light flash intensity was obtained based on original data and calibration by Matlab programmable treatments under the given experimental condition and the optical-fiber probe scheme. Evolutionary characteristics of radiation temperature were acquired by using ratio methods. Experimental results show that impact light flash intensity and radiation temperature peak value decrease with impact angles increasing in the range of 488 to 667 nm during hypervelocity impact on LY12 Aluminum targets.