Objective: For efficacy, pregnant women often use the COVID-19 rapid antigen test result as the basis for hospitalization or transfer to special wards. However, the accuracy of the rapid antigen test is low. We reported the hospitalization process of a case negative in the rapid test which turned positive in the nucleic acid test and successful blocking of nosocomial infection to be used as a reference for institutional infection control. Case Report: A 34 years old parturient woman who had a Caesarean section in the last born came to the hospital at 37 gestational weeks with pre-delivery signs. She was admitted after a negative COVID-19 rapid antigen test, but due to the unknown result of the nucleic acid test, she was treated and cared at a confirmed case level. After the operation, she was diagnosed with a positive COVID-19 infection in nucleic acid test (CT value 35) and transferred to the isolation ward for further treatment. All follow-up COVID-19 nucleic acid tests for the contacted medical staff members were negative. Conclusion: For high-risk parturient women with negative COVID-19 rapid antigen test, proper protection is still required during delivery to prevent the occurrence of nosocomial infections.