Radio Frequency Identification (RFID) technology is applied more widely in industry and daily life. One type of RFID product, passive tag, has many advantages over another type, battery-based active tag, such as longer product life, smaller size, lower cost, etc. Due to very low price of passive tag, how to test it fast and efficiently in production is a big challenge to ATE (Automatic Test ... [Show full abstract] Equipment) engineers. The non-deterministic latency from stimulus to response also brings much difficulty to testing. This paper introduces a complete ATE-based solution for testing of 13.56 MHz RFID passive tag, including a dedicated module to generate, filter and amplify modulation signal, and a real-time verification method, which overcomes the difficulty caused by non-deterministic latency. The paper demonstrates advantages of the real-time method by comparing test time with result of traditional method of data capturing then post processing.