<p>High precision is crucial for industrial development, and lightweight design is widely recognized as a key direction for industrial upgrading. Accurate alternating current (AC) magnetization curves of current transformers can achieve high-precision measurement and product lightweight design from a design perspective. We constructed a high-precision AC magnetization curve measurement system and, from the research perspective, obtained the fundamental magnetic characteristic dataset for the material—namely, the measured data of the ultracrystalline core. The existing AC magnetization curve function analytical expressions were evaluated using the measured data, and a new empirical function analytical expression was proposed. This new expression is simple to use and sufficiently accurate, featuring eight parameters, with an adjusted R² of 1 for <i>H</i> = <i>f</i>(<i>B)</i> and 0.9995 for <i>ψ</i> = <i>f</i>(<i>H</i>). The empirically derived analytical expression was subsequently embedded in the core-manufacturing computation routine; from the manufacturing perspective, core quality was assessed by comparing core control data with the embedded model to discriminate between conforming and defective cores. Finally, error test results obtained from the application side were analyzed to validate the method. This unified optimization across the research, manufacturing and application domains drives the advancement of the entire industrial chain.</p>