In this article, a theoretical model for predicting the equilibrium morphology of gas-liquid Janus droplets was built. Based on this model, the effects of bubble radius and volume ratio on morphology change was systematically studied. The increase of bubble radius causes the two parts (bubble and oil drop) in Janus droplets tend to merge while the impact of volume ratio is complicated. When volume ratio increases, these two parts firstly tend to merge, then gradually separate. The accuracy of this model was verified by experimental results. (C) 2018 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.