Abstract: The purpose was to provide theoretical basis for developing natural colorant from cactus pear fruit. The extraction process conditions were established for red pigment from cactus pear fruit. The stability of the red pigment was researched. The best extraction process condition was as following, extraction agent was 70% ethanol solution, material and extraction agent ratio was 1∶ 20 (w/v) , pH5. 0, extraction temperature for 50℃, the extraction time for 1h. The results showed that the red pigment from cactus pear fruit was stable at pH3 ~ 5, but was unstable to sunlight, oxidizing agent, reducing agent. It was stable to Na+ and Mg2+, but unstably to Zn2+, Sn2+, Fe3+, Cu2+ and Pb2+.