Big data technology is widely used in the prevention and control of new coronavirus epidemic. The disclosure of epidemic information improves the effectiveness of epidemic prevention and control, but frequent privacy leaks also pose problems. The scope of privacy in the era of big data has been expanded, and individuals should accept restrictions on their privacy for public welfare purpose if such restrictions are legal and moderate. In the prevention and control of covid-19 epidemic, individual privacy protection faces such dilemmas: failure of the informed consent rule, conflict between the public and the personal interests, and conflict between the public right to know and the personal right to privacy. To protect personal privacy, we must strictly regulate the information disclosure activities, first to follow relevant legal principles to ensure its legality, secondly to guarantee the public rights of knowledge, consent and supervision to ensure its transparency, and finally to strictly implement the system of privacy tort liability and strictly observe the last legal defense for privacy protection.