Abstract: A cooling system performance early warning method based on dictionary learning is disclosed. A sensor and an oil pump frequency converter are arranged on a cooler of the cooling system to measure operation data of the cooling system. A PLC controller is installed on the cooler to collect the measured operation data and connected with a cloud server, and the cloud server first performs offline dictionary learning on the data, so as to establish a performance cads warning model for each group of coolers respectively. After the offline dictionary learning stage is completed, an online early warning stage is entered, and the established performance early warning model is used to carry out a real-time performance early warning of the cooling system. The early warning method can use the established performance early warning model to carry out real-time performance early warning, which has the advantages of real-time, realizability and strong pertinence.