Using an intensified spectroscopic detector CCD, the UV-Vis absorption spectra of tanshinone ⅡA and Tanshinone ⅡA-Cu(Ⅱ) complex were acquired. The stable geometric structures of Tanshinone ⅡA and TanshinoneⅡA -Cu(Ⅱ) complex were obtained by using density functional theory method. Based on the optimized geometric structures, the electronic absorption spectra of Tanshinone ⅡA and TanshinoneⅡA-Cu(Ⅱ) complex in gas phase and in ethanol solution were calculated by using time-dependent density functional theory. Results show that the solvent effect induces the red shift of spectrum for Tanshinone ⅡA and the blue shift of spectrum for Tanshinone ⅡA-Cu(Ⅱ) complex. The calculated absorption spectra including the solvent effect are in good agreement with the experimental results. The present work first measured and computed the electronic absorption spectra of Tanshinone ⅡA-Cu(Ⅱ) complex.