In this study, natural canthaxanthin (CTX) as one of the most important carotenoids was extracted from Dietzia natronolimnaea HS-1. The changes of CTX enriched in oil-in-water emulsions with vegetable oil (5 mg/100 ml), Arabic gum (5 mg/100 ml), and potassium sorbate (0.5 g/100 ml) were investigated. The effects of different pH (3, 5 and 7) and time treatment (3, 18 and 33 days) in the room temperature (24±1°C) on the colour degradation were studied by response surface methodology (RSM). A second-order polynomial equation fitted to the data was used to predict the responses in the optimal region. The responses were Hunter values (L*, a*, and b*) and CTX concentration (mg/l). Results illustrated more degradation of this pigment at low pHs (pH £4) by passing the time (days³10) with high R² of 97.00%, 91.31%, 97.60%, and 99.54% for CTX, L*, a*, and b* respectively. The predicted values were in good agreement with experimental data and thus the model was found to be significant (p < 0.05).