The testing of a 5G chip is a new domain to OSAT, especially for mmWave testing with OTA solution for AiP device. Although the development of test instrument is on track to explore the effective solution for testing industry, there are still many challenges for OSAT to deliver high quality 5G chips to customers. This presentation will discuss the test challenges of 5G technology and the impacts to test houses. The test setup of mmWave is complicated with low parallelism for production test. To reduce the test cost of 5G chip, we will work in close collaboration with supply chains for providing cost-effective solution.