Abstract: ²³⁷Np is a highly toxic nuclide, which can cause internal exposure hazards after inhalation. The analysis of ²³⁷Np based on urine samples is an important method for routine monitoring, as well as a key method for studying the dose level of ²³⁷Np  in the human body of professional workers. The pretreatment process of ²³⁷Np in large-volume urine samples, pre-concentration by co-precipitation, and the effect of TEVA resin separation and purification and electrodeposition on the chemical recovery of ²³⁷Np were systematically studied and discussed. The research results show that the chemical recovery of the experimental method can reach 88.5%, and the detection limit of the method is 2.55×10^-5 Bq/L. This analysis method meets the requirements of routine monitoring and is suitable for monitoring and evaluating ²³⁷Np in large-volume urine samples.