Abstract: Based on Box-Behnken center composite design within Design-Expert7. 0 software and response surface results, the optimal extraction process for carotenoids from Lethariella spp. were determined and a regression model was established. On the basis of single factor tests, using absorbance values in a specific wavelength of carotenoids as response value, three key factors (solid-liquid ratio, extraction temperature and time) were selected as independent variables and acetone as extraction solvent. The results showed that the optimal extraction process of carotenoids from Lethariella spp. was obtained as followed:solid-liquid ratio of 1∶3 (g/mL) , extraction temperature of 52℃, and extraction time of 20min. Under these conditions, the extraction of carotenoids from Lethariella spp. absorbance was 0.3682, i. e. 22.092μg from per g Lethariella spp. raw materials. The results showed that regression equation fit well with experimental data because of a good accordance between the predicted and observe values. Meanwhile the optimized technology was stable and viable with minor error and good degree.