A new automatic weather station, which is capable to add new sensors, is developed based on the advanced CAN technology. The software, hardware, lightning protection, processing speed, and storage capacity of the new automatic weather station are improved. Developed from the operational software OSSMO 2004, the new version OSSMO 2010 is stable, flexible, extensible, and usable. Aiming to discuss differences between the two versions, comparison ansd analysis are conducted. Some changes in parameter settings, data files, radiation and evaporation data maintenance in OSSMO 2010 are made, and the data processing of OSSMO 2010 is the same as OSSMO 2004 Using this method, the seamless integration of observation can be realized. The particular differences and processing methods of the software are discussed, which is useful for observers in stations to be familiar with OSSMO 2010 quickly.