Abstract: Hybrid K-edge/XRF densitometer (HKED) is widely used for concentration simultaneous analyses of uranium and plutonium in spent fuel dissolution. HKED hardware structure and its characteristics were introduced in this paper. Depending on the site’s condition and object’s characteristic, the parameters were optimized, and the system was calibrated. HKED was applied in the advanced Purex process based on salt-free regent active test. It is validated that the uranium concentration precision for 1AF samples is up to 0.3%.