When β cyclodextrin(β CD) was used as a catalyst for the oxidation of benzyl alcohol in water，benzyl alcohol and the oxidative product benzaldehyde could coexist stably in the cavity of β CD.The stable inclusion of β CD and benzyl alcohol(benzaldehyde) could be automatically formed in water with a molar ratio of 1∶1，and the standard Gibbs functions of molar reaction ΔγGmθ(298 K) of benzyl alcohol(benzaldehyde) were -10417 kJ/mol and -9741 kJ/mol，respectively.The ultraviolet absorption spectra of benzyl alcohol and benzaldehyde indicated that the presence of β CD could result in the enhancement of absorption intensities of benzyl alcohol and benzaldehyde.A good linearity was obtained between the UV-absorption intensity of the system and the concentration of benzyl alcohol(benzaldehyde).Based on this，a novel enlarged ultraviolet absorption spectrometry method for the determination of aromatic organic compounds was established.The precision of this quantitative determination could reach up to 98% or more，and the determination ranges were also greatly improved.A quick and accurate method was provided for the monitoring of reaction systems in the aqueous β CD solution.