Abstract: FY-3 series is a new generation of polar-orbiting meteorological satellite which is much more powerful than FY-1 series. As the first research and development satellite of FY-3 series, FY-3A meteorological satellite carries 11 kinds of instruments with more than 90 observation and probing channels, and it has the capabilities of global sounding, global imaging of the earth's surfaces and natural color imagery with a higher spatial resolution of 250 m. The size of the raw data files for one pass of FY-3 meteorological satellite is almost 100 times as FY-1. There are 4 domestic ground stations set up in China, and they are located in Beijing, Guangzhou, Urumqi and Jiamusi respectively. These 4 ground stations are responsible for receiving the FY-3 satellite observation data and transferring them to the data processing center which is located inside the building of National Satellite Meteorological Center in Beijing. It is really a big challenge for the data transmission system of the FY-3 satellite to transfer the massive meteorological satellite observation data efficiently and timely from the ground stations to the data processing center.The WAN acceleration technique is studied to solve the problems such as high delay in transmission of massive satellite observation data and little bandwidth utilization during WAN link. To deal with the data transfer characteristics of FY-3 properly, massive observation data and high-timeliness requirement for instance, the transmission optimization effects of three different acceleration techniques, including data compression, cache and TCP protocol optimization on meteorological satellite data are analyzed respectively. According to the analysis results, a WAN data transmission acceleration architecture which is suitable to FY-3 satellite observation data transmission is illustrated and presented to break the bottleneck of data transmission through WAN. This architecture combines TCP proxy module, segment index module and HS-TCP transfer module by integrating three different acceleration techniques to realize the key functions such as data compression, cache and protocol optimization. Experimental and operational practices show that this WAN data transmission acceleration architecture results in impressive acceleration, and FY-3 satellite data transmission rate through the WAN is accelerated up to 50%—243%.