A (controller area network) CAN filter combining method and a CNA controller are provided. The CAN filter includes a special filter and one or more common filters. The method includes: initializing a mask code and at least two filter codes of the special filter, acquiring a first total number of the filter codes in the special filter and a second total number of the common filters, acquiring mask codes and filter codes of the common filters, and adjusting the mask code and the filter codes of the special filter on the basis of the first total number, the second total number, and the mask codes and the filtering codes of all of the common filters. The method reduces the load of a processor, and prevents the CAN controller from processing a large amount of irrelevant data, thereby accelerating communications.