With the rapid development of industrialization, the problem of concentration determination based on the copper production process has been widely concerned, and the accurate determination of high-concentration copper ions (Cu2+) is of great significance for enterprise production, resource utilization, and pollution prevention. The characteristics of different spectrophotometric methods for the determination of Cu2+ are discussed, and it is found that these methods are suitable for the determination of trace or low concentration of Cu2+ (0.5 μg/L–5 mg/L), whereas for the determination of high Cu2+ concentration pre-treatments such as dilution, complexation, and coloring are required. In this study, a method based on ultraviolet-visible spectroscopy (UV-Vis) combined with partial least squares regression analysis (PLS) was proposed for the determination of high copper ions (>100 mg/L), which performs rapid and accurate determination of high Cu2+ concentration by preprocessing and feature extraction of UV-Vis spectral data, followed by model construction with PLS analysis, which is easy to operate and applicable to a wide range of concentrations. The correlation coefficient (R2), mean relative error (MRE), and root mean square error (RMSECV) of the model prediction of Cu2+ concentrations were 0.99946, 0.006343, and 11.237 mg/L, respectively, indicating that the accuracy of the model prediction is very high. This study not only provides an efficient method for the precise determination of high Cu2+ concentration but also enables the simultaneous determination of Cu2+, Co2+, and Ni2+ ions, which provides a new technical means for environmental monitoring and pollution prevention.