The influence factors on carotenoids extraction from nonsulphur purple bacteria were researched, which included extraction time, extraction temperature, solvent dosage and saponification. And primary analysis for the carotenoids extraction was made. As a results, the best extraction temperature was 49℃, the best extraction time was 4 hours and the best solve dosage was 5 milliliters acetone to one gram bacteria mud. Then Saponification could get rid of residue chlorophyll from cartoenoids and hydrolyze carotenoids esters，so that it improved its purity.