With the development of scientific technology, more and more methods are being used in automatic weather observation. However, presently weather phenomenon observation is mainly conducted manually. The researches are carried out on the present situation of automatic weather observation of weather phenomenon at home and abroad, trying to find the ways to realize the automatic observation of 34 weather phenomena based on their characteristics. The results show that the automatic recording of most weather phenomena can be realized. Besides, the approach to establish the WMO weather codes automatically is presented. In all of the 100 codes, 63 codes may be automatically established.