The symptoms of the election, the rule of law, media and civil society show the autocratization trend in Hong Kong. As the quality of global democracy regresses, scholars focus on and propose the concept of autocratization as the pattern of backsliding after the third wave of democratization. According Electoral Democracy Index and Liberal Democracy Index promulgated by V-Dem, Hong Kong’s situation in the last 10 years correspond to the definition and threshold of autocratization. The case of Hong Kong autocratization can be ascribed to the autocracy promotion and diffusion of China. We utilize the datum of the China Impact Survey from 2016 to 2020, to analyse how autocratizaion affects the desired regime type of Hong Kong society. Also, we will test five assumptions that derive from factors that may cause autocratic diffusion. For example, national identity, frequency of visiting China, the evaluation towards the importance of China's consumption market, confidence towards China future development and taking advantage from China-Hong Kong economic relations or not. The outcome shows that Hong Kong society decreased its support towards autocracy. The chance of supporting democracy increased can be identified, rather than reduced in other cases. National identity, confidence in China future development and the subjective beneficiary of China-Hong Kong economic relations significantly increase the chance of supporting autocracy. The case of Hong Kong autocratization shows the importance and effect of external autocratizer, China as an autocratizer and the democratic resilience of Hong Kong society.