The invention provides an automatic irrigation apparatus, and a control method of automatic irrigation. The automatic irrigation apparatus comprises: a fertilizer mixing device connected with one end of a self-circulating device and used for preparing a nutrient solution and conveying the nutrient solution to the self-circulating device; an adjusting device, wherein one end of the adjusting device is connected with the other end of the self-circulating device, the other end of the adjusting device is connected with the fertilizer mixing device, and the adjusting device is used for adjusting the concentration of the nutrient solution in the self-circulating device; and a waste liquid discharging device connected with the self-circulating device and used for discharging the nutrient solution in the self-circulating device. The automatic irrigation apparatus has the advantages of realization of the automatic adjustment of the concentration of a leafy vegetable nutrient solution, the automatic circulation of the nutrient solution and the reutilization of the nutrient solution waste liquid, realization of use maximization of water and fertilizers, and reduction of the pollutions discharged to the nature.