In recent years, in order to solve the problem of small and medium-sized micro enterprises' loan difficulty, the major banks have developed some very relaxed microloan businesses under the guidance of the policy. These businesses help the vigorous development of small and micro enterprises, but also bring the problem of non-performing loan ratio increasing year by year. In 2020, due to the influence of COVID-19, this problem became particularly acute. The sharp increase in the non-performing loan rate posed new challenges to the credit risk management of banks. Do these enterprises have some warning features when they apply for loans before the epidemic? This problem is worthy of further exploration. Therefore, this paper used the LAD method to analyze the approval data of small and medium-sized micro enterprises (SMEs) approved for online loans in XX Branch of N bank in 2019, excavated the pattern characteristics of SMEs with non-performing loans after the epidemic, help banks with similar problems to improve the credit risk assessment mechanism, improve their early warning ability against the epidemic and other force majeure factors, and reduce the systemic financial risk Insurance, maintain financial stability.