Both the gas fingerprint chromatography and the preprocessing of reverse liquid chromatogram have shown their faults in calculating oil production allocation of mingling recovery wells.These faults could be solved through the determination of the concentration of metallic ions in multi-component systems by partial least-square ultraviolet spectrometry. Oils in different horizons have different ultraviolet spectrum absorption. The linear stacking relationship between crude oil absorptivity and oil production allocation percentage could be established according to Lambert-Beer's law

and oil production allocation of each end member could be calculated.Following points should be taken into acount in data processing by this method: 1.betterlinearrelationship between the absorbance and concentration in selected wavelength range(interval); 2.selecting data with great difference of absorptivity in the interval of 200～400 nm wavelength; 3.selecting quantitative analysis in the range of peak tops; 4.avoiding sharp peaks.