Abstract: In the background of advancing the modernization of the national governance capabilities and system, big data technology is widely used in police law enforcement.Based on this, the article uses the research methods of normative, case and comparative analysis to study the technical logic, practical application, social risks and legal control of big data policing.In the practice of big data policing, “dirty data” often leads to threats to citizens’ equal rights protection.The massive collection, processing and use of personal data by police agencies infringes on personal information privacy.The algorithm systems have no transparency and accountability mechanism, which leads to the lack of effective relief for personal rights.In order to prevent the alienation of big data policing, China should formulate police data collection laws to ensure the reasonable use of personal data, establish risk assessment system to regularly detect the risks of the big data policing, give the public the right of algorithm interpretation and strengthen the public accountability.