Abstract: ²⁴¹Am belongs to the alpha nuclides of the extremely toxic group, which will cause internal exposure hazards when inhaled into the human body. Urine sample analysis and monitoring technology is one of the important methods for monitoring the internal exposure of workers. In this paper, the analysis and monitoring technology of internal exposure urine samples was established by studying the pretreatment, separation and purification, electroplating and other factors of large volume urine samples. At the same time, the research on the monitoring and evaluation technology of the analysis technology in ²⁴¹Am was investigated. The results show that the chemical recovery rate of the established internal exposure urine sample analysis and monitoring technology is 86.2%, the precision is 3.88%, the relative deviation is less than 10%, the decontamination coefficient for Pu is greater than 1.0×10³, and the detection limit is 31.8 μBq/L. For 1.6 L 24 h urine sample and 360 d monitoring regular cycle, the minimum measurable effective dose is 0.13 mSv, lower than the routine monitoring survey level of 2 mSv. The analysis and monitoring technology of internal exposure urine samples is suitable for routine monitoring of urine samples in professional ²⁴¹Am and dose evaluation.