The invention discloses a sub-zone NOX generation amount-based ammonia spraying optimizing adjustment method. The method comprises the following steps: determining the pressure difference of the pressure exit point of every ammonia spraying branch tube, calculating the sum of the pressures of all branch tubes, querying the butterfly valve flow characteristic curve of the ammonia spraying branch tubes, and searching the branch tube flow corresponding to the current opening degree of every ammonia spraying branch tube to obtain the branch tube flow corresponding to per unit pressure; determining the NOX concentration of sub-zones corresponding to the ammonia spraying branch tubes, and calculating the sum of all the pressure values; and determining the smoke flue velocity of the sub-zone corresponding to every ammonia spraying branch tube, calculating the flow ratio of every ammonia spraying branch tube, calculating the flow of every ammonia spraying branch tube, searching the current valve opening degree (%) corresponding to every ammonia spraying branch tube, and manually adjusting the valves. The method is simple, and is an ammonia spraying method for rapidly and accurately realizing optimizing adjustment through calculating obtained data of all position determination parameters.