During the past 30 years, several types of nuclear power plants have gained importance in China; these primarily include CPR1000, Russian advanced pressurized water reactor (WWER), passive advanced pressurized water reactor (AP1000) and European advanced pressurized water reactor (EPR). The treatment technologies for the radioactive solid, liquid, and gaseous wastes adopted by various types of nuclear power plants are different; consequently, emission control requirements and specifications for gaseous and liquid effluents also vary accordingly. Especially, the alarm thresholds of gaseous effluent radiation monitoring from nuclear power plants are highly concerned by the regulatory agencies since they determine the upper limit of the emission amount of gaseous radioactivity under normal operation and provide the alarm timely in case of accidents. In this paper, the setting method and basis of the radiation monitoring alarm thresholds for gaseous effluents from various nuclear power plants in China are examined, and the calculation method for the alarm thresholds is compared and analyzed. The unified setting principles and methods for pressurized water reactors (PWRs) are proposed, which can serve as a reference for setting and reviewing the radiation monitoring alarm thresholds of the gaseous effluents from the new nuclear power plants in China, and supply technical support for the improvement of the related regulations and standards for the nuclear power plants in future.