Two methods assessing the year's harvest of cotton are introduced. One is comprehensive element and another is analogous analysis. The first is that a assessing index is given by analysing historical comprehensive meteorological element, which is adequately established by using ten-days' mean temperature,ten-days' precipitation and sunshine hours of AB telex data,and bumper or poor harvest of cotton. In the second, typical year of failure or good harvest of cotton is firstly defined. Analogous analysis indexes were attained by using principle of similar analysis. It is shown that their accuracy can reach more than 90% on adjudging bumper or poor harvest of cotton by using these indexes.