A pressure drop control system for a feed distributor of a fluidized bed ammoxidation reactor, the pressure drop control system comprises: a measuring unit which is configured to measure a pressure drop between a first pressure measurement port and a second pressure measurement port of the feed distributor, wherein the first pressure measurement port is located in an inlet tube of the feed distributor near a reactor wall of the fluidized bed reactor, and the second pressure measurement port is located in an area of the reactor wall between an air distribution plate of the fluidized bed reactor and a gas outlet of a nozzle of the feed distributor, characterized in that a transfer unit which is configured to carry on signal communications with the measuring unit and collect a signal about the pressure drop measured by the measuring unit, and a processing unit which is configured to monitor whether the feed distributor is working normally or not, wherein when a pressure drop of the feed distributor is in a predetermined scope within which the pressure drop of the feed distributor is 25%-160% of a pressure drop of a bed of the fluidized bed reactor, the processing unit determines that the feed distributor is working normally, and wherein when the processing unit determines that the pressure drop of the feed distributor is larger than an upper limit value or smaller than a lower limit value of the predetermined scope, the processing unit performs corresponding actions so as to restore the pressure drop of the feed distributor to a value within the predetermined scope, and the pressure drop control system further comprises a nitrogen purging device, when the processing unit determines that the pressure drop of the feed distributor is larger than the upper limit value of the predetermined scope, the processing unit is configured to turn on the nitrogen purging device so that the feed distributor can be purged. a measuring unit which is configured to measure a pressure drop between a first pressure measurement port and a second pressure measurement port of the feed distributor, wherein the first pressure measurement port is located in an inlet tube of the feed distributor near a reactor wall of the fluidized bed reactor, and the second pressure measurement port is located in an area of the reactor wall between an air distribution plate of the fluidized bed reactor and a gas outlet of a nozzle of the feed distributor, characterized in that wherein the first pressure measurement port is located in an inlet tube of the feed distributor near a reactor wall of the fluidized bed reactor, and the second pressure measurement port is located in an area of the reactor wall between an air distribution plate of the fluidized bed reactor and a gas outlet of a nozzle of the feed distributor, characterized in that a transfer unit which is configured to carry on signal communications with the measuring unit and collect a signal about the pressure drop measured by the measuring unit, and a processing unit which is configured to monitor whether the feed distributor is working normally or not, wherein when a pressure drop of the feed distributor is in a predetermined scope within which the pressure drop of the feed distributor is 25%-160% of a pressure drop of a bed of the fluidized bed reactor, the processing unit determines that the feed distributor is working normally, and wherein when the processing unit determines that the pressure drop of the feed distributor is larger than an upper limit value or smaller than a lower limit value of the predetermined scope, the processing unit performs corresponding actions so as to restore the pressure drop of the feed distributor to a value within the predetermined scope, and the pressure drop control system further comprises a nitrogen purging device, when the processing unit determines that the pressure drop of the feed distributor is larger than the upper limit value of the predetermined scope, the processing unit is configured to turn on the nitrogen purging device so that the feed distributor can be purged. wherein when a pressure drop of the feed distributor is in a predetermined scope within which the pressure drop of the feed distributor is 25%-160% of a pressure drop of a bed of the fluidized bed reactor, the processing unit determines that the feed distributor is working normally, and wherein when the processing unit determines that the pressure drop of the feed distributor is larger than an upper limit value or smaller than a lower limit value of the predetermined scope, the processing unit performs corresponding actions so as to restore the pressure drop of the feed distributor to a value within the predetermined scope, and the pressure drop control system further comprises a nitrogen purging device, when the processing unit determines that the pressure drop of the feed distributor is larger than the upper limit value of the predetermined scope, the processing unit is configured to turn on the nitrogen purging device so that the feed distributor can be purged.