To address the technical bottleneck of measuring radioactive resin interfaces in nuclear engineering, a resin material interface data acquisition system was proposed, and a corresponding digital control system was developed to solve the problem of float ball jamming and burial. After repeated experimental verification, the system’s reliable motion in a fully turbid liquid environment was confirmed, with a double float ball signal positioning error controlled within ±1.2 mm. By combining a magnetostrictive sensor with an intelligent control algorithm, the limitation of traditional electromagnetic wave measurement failure was overcome, successfully achieving interface recognition in a medium with a density close to that of water (relative density 1.07–1.12 g/cm3), and avoiding reliance on encoders in a radioactive environment. The precise positioning of 99% of the range was completed through closed-loop control of the float ball position.