The invention discloses a method for compiling a port atmospheric pollutant discharge inventory based on activities. The method comprises a method for estimating discharge of port ships, a method for estimating discharge of harbour boats, a method for estimating discharge of port machines, a method for estimating discharge of heavy trucks, a method for estimating discharge of switch engines and a method for estimating the discharge amount of main transport locomotives. According to the method for compiling the port atmospheric pollutant discharge inventory based on activities provided by the invention, the port atmospheric pollutant discharge inventory is established based on port activities aiming at discharge sources, such as the port machines, the port ships, the harbour boats, the main transport locomotives and the switch engines; therefore, the source and pool relationship of a port and atmospheric pollutants in the inland navigation industry is known easily; the environmental situation of the shipping industry is correctly judged easily; and scientific basis is provided for setting reasonable policies and measures of a discharge reduction scheme in the shipping industry.