Operating IT equipment safely and resiliently in a data center requires strictly cooling management. Many important aspects that need to be considered simultaneously as required cooling capacity reserve of the IT heat load, cold airflow reserve, and ability to dissipate heat in the hot corridor to avoid the appearance of local hot spots with high hot air density. Taking the actual computer room and power room of small-scale data center in operation for five years as an example, thermal distribution included cold air IT inlet and hot air exhaust of data center in different scenarios were simulated, and temperature and airflow rate were analyzed. CFD simulation was carried out for the real-operation condition used computer room. The study shows that cold and hot air recirculation sides, which reduces the utilization of cold air and effectiveness of exhaust air to coolers. The research carried out on thermal management of data centers has helped improve cooling performance in many instances (risk of hotpots from the high-density hot air due to the limitation of hot aisle dimension). We expect further improvements to all aspects of data center design and operation in the near future, with a focus on real-time measurement and cold/hot airflow control in addition to CFD thermal simulation.