Abstract: To compare the influence of each parameter on insulation resistance of the assembly self-powered neutron detector and to further solve the problem of improving installation from the aspect of structure design, insulation resistance models of the detector probe part, leader cable part and whole detector were established in this paper based on the structure characteristics of the assembly self-powered neutron detector. Influence of material resistivity,tolerance clearance between the emitter and the insulation shell, emitter eccentricity,connection length between emitter and signal conductor, and leader cable length on insulation resistance value was studied and analyzed. Through theoretical calculation, the influence of emitter eccentricity and tolerance clearance between the emitter and insulation shell on whole insulation resistance of the detector is negligible. The leader cable length of the detector is the critical factor for whole insulation resistance of the detector, especially for the self-powered neutron detector of which the leader cable length is more than 10 meters. This paper can provide reference for the structure design of self-powered neutron detector.