In order to propose the method of evaluating and improving the real-time performance of EPA (Ethernet for plant automation) industrial Ethernet, the real-time performance of EPA information transmission was studied from theoretical and experimental perspectives. By analyzing information transmission regularity and EPA deterministic scheduling mechanism, several indicators including delivery time, time synchronization accuracy, utilization percentage of configured timeslice, datasending time offset accuracy and throughput RTE that can be used to specify the real-time performance of EPA information transmission were presented and investigated. On this basis, the test principles and test methods of the indicators were studied. Furthermore, an experiment platform was developed to test the real-time indicators of EPA information transmission. According to the analysis and the experiment, some methods to improve the real-time performance of EPA information transmission were proposed.