The invention discloses an automatic temperature control method for a granary air conditioner based on a temperature field cloud map. The method comprises the following steps that firstly, grain temperature data are acquired, the grain temperature data are rearranged according to the layout of sensors in a granary, data processing is carried out on the arranged grain temperature data, and missinggrain temperature data between sensor arrays and outside the sensor arrays are complemented; secondly, the temperature field cloud map of the granary is obtained according to the grain temperature data after the data processing; thirdly, after the first area, the second area, the third area and the fourth area which are converted to the actual space are calculated correspondingly, the first area change rate, the second area change rate, the third area change rate and the fourth area change rate of the adjacent two days are calculated; and fourthly, the granary air conditioner is controlled asfollows: judgment is carried out according to the threshold interval of the grain temperature, cooling treatment is carried out according to the cooling level when the area and area change rate conditions are met in the threshold interval, and otherwise, one level down treatment is automatically carried out.