Over the past three years, the construction of 5G communication has been the hottest topic. In April 2019, the first 5G network was established in South Korea, 5G network construction developed from South Korea to China, and then to North America and the other regions in the world. Passive WDM products have become one of the three important parts of 5G telecom system. As one of the biggest passive WDM manufacturers in the world, Flyin Optronics has got the chances to supply the passive WDM to the different operators in the past three years. According to our experience, we would like to share and introduce the different requirements and standards of passive WDM in 5G networks in different countries, including different product designs, different optical performance parameters and reliability requirements.