A surge in the workload of the hospital for testing potential patients and an increased risk of cross-infection among patients due to emergent epidemic, poses a critical social public safety problem. Through the methods including literature review, epidemiological theory, expert consultation，subjective weighting （involving experts from the Departments of Infection Control, Respiratory Medicine, Critical Care, and the Center for Disease Control）, human-computer interactive design，user test，usability evaluation and etc，the content of online affected risk self-check application, available options, risk weighting and threshold, and human-computer interactions of high usability are investigate. An early prevention and control strategy is proposed for suspected cases screening and reliable suggestions to self-monitor at home, self-isolate, or seek immediate medical attention. The human-computer interaction application and screening model for suspected symptom risk assessment are designed and promoted online. The results indicate that in the early phase of emergent epidemic, the online emergent epidemic affected risk self-check application can provide a simple and feasible scientific basis for clinical judgement, alleviate the social panic, resolve the shortage of manual screening, and reduce the risk of cross-infection among patients by providing a straightforward, easy-to-understand scientific protocol. It provides references for future new epidemics prevention and control through online classification and offline triage of patients of suspected symptoms.