The invention discloses a method for detecting the inherent error of ammonia volatilization of a farmland by an in-situ synchronous correction static chamber method. The method comprises the following steps: firstly, preparing ammonia solutions with different concentrations by adopting an ammonium sulfate reagent, and putting the ammonia solutions in farmlands with crispers to serve as different simulated ammonia volatilization sources with different volatilization strengths; respectively putting the simulated ammonia volatilization sources in a farmland natural environment and a static chamber method detection device to simulate actual ammonia volatilization and ammonia volatilization in the device, synchronously detecting the simulated ammonia volatilization source and ammonia volatilization of farmland at the same time interval, adding sodium carbonate into the simulated ammonia volatilization source to start ammonia volatilization, and terminating the ammonia volatilization process with a diluted sulfuric acid solution when the stage ammonia volatilization is completed; calculating the volatilizing speed of the simulated ammonia volatilization source and farmland volatilization after sampling is completed, preparing a correction curve by the ratio of ammonia volatilization speed at two environments and the ammonia volatilizing speed in the static chamber method detection device, and acquiring the farmland ammonia volatilizing speed with corrected environmental disturbance inherent error through the correction curve. According to the method, the inherent detection error caused by static chamber method sampling device disturbing natural environment can be greatly reduced.