During the Cassini Grand Finale mission, this spacecraft, for the first time, has done the in-situ measurements of Saturn’s upper atmosphere and its rings and provides critical information for understanding the interaction between the main rings and the Saturnian system. The ring atmosphere is the source of neutrals, which is primarily generated by photolytic decomposition of water ice, and plasma in the Saturnian magnetosphere. In addition, the main rings have strong interaction with Saturn’s atmosphere and ionosphere possibly through the grain impacts, neutral diffusion and current exchange. The data now coming from Cassini Grand Finale mission already shed light on the dominant physics and chemistry in this region of Saturn’s magnetosphere, for example, the presence of carbonaceous material from meteorite impacts in the main rings and each gas species have similar distribution in the ring atmosphere. With the updated Cassini measurements, we will revisit the details in the already-developed ring atmosphere/ionosphere model to study, such as the source mechanism for the organic material and the neutral-grain-plasma interaction processes.