Since the arrival of the Web2． 0 era，network media gradually dominates public opinion generation， dissemination and exchange． The evolution and alienation of public opinion crisis has become a serious social problem，which received increasing attention from social scientists and the general public． Therefore，the pa-per chooses the alienation mechanism of network public opinion crisis as the research object． After collecting and sorting public opinion crisis incidents in recent years，the basic concepts，expression forms，and specific patterns of public opinion alienation are systematically summarized． Then，under the architecture of public o-pinion supernetwork，the polarization algorithm of public opinion crisis alienation is proposed，which can be used to analyze the driving factors of alienation mechanism． Besides，the paper also presents a concrete scheme and program codes of the polarization algorithm． In the case study section，the polarization process and influencing factor are discussed by using the polarization algorithm．