Abstract: Madden-Julian Oscillation (MJO) or more generally called tropical Intra-Seasonal Oscillation (ISO), dominates climate variability worldwide on the subseasonal timescale. It is well-known that MJO can impact weather and climate not only in tropics, but also in extratropics through the propagation and excitation of atmospheric teleconnections, and is the most important predictability source in the subseasonal-to-seasonal prediction. A great many studies have focused on impacts of MJO on weather and climate in China in the past decades, and made a significant progress in different aspects. However, further deep understanding is still needed. This study firstly reviews previous studies of impacts of MJO on China weather and climate, and then shows the new results regarding such impacts of MJO, based on diagnoses of new observations, then gives preliminary conclusionsas followings:. the impacts of MJO on rainfall are mainly limited in the regions from south of Yangtze River to the South of China in winter, but are extended to the more southern and Tibetan Plateau areas in summer. It shows a significant influence of MJO on winter temperature over the Northeast of China, the North of China, and most of the western China, while a relatively weakened impact on summer temperature over the large areas in China except for the Yellow River Basin. After removing high-frequency noise, pure MJO signal can explain about 30% variance of low-frequency surface air temperature and rainfall in China. Moreover, it is found that there is a delayed impact of MJO on temperature and rainfall in both winter and summer in China and it is need to be consideredin the future predictions and futher studies.