The invention belongs to the technical field of nuclear safety monitoring, and relates to a sensor arrangement method for a large pressurized water reactor containment vessel overall sealing performance test. The method successively comprises the following steps that (1) relevant information including the elevation of each compartment in the workshop of a large pressurized water reactor containment vessel is collected and collated, and the total free volume of large space of the containment vessel and the free volume of each compartment of the internal part are calculated; 2) the compartmentsin the containment vessel are grouped according to the elevation of each floor of the containment vessel; (3) the relevant compartments of the same group are appropriately combined according to the compartment conditions; and (4) the volume weight coefficient of each group is calculated according to the grouping and combining result of the step (2) and the step (3), and the sensor positions are finally determined according to the actual compartment positions so that the arrangement scheme can be completed. With application of the method, the temperature and humidity data in the pressurized water reactor containment vessel can be truly and representatively measured through the arranged sensors in the containment vessel overall sealing performance test.