The laser-induced fluorescence excitation spectrum of the A2∑- - X2Ⅱ3/2 transition of CuO in the 540-620nmregion has been studied, where the CuO molecule was produced by using the technique of dc discharge reaction undera supersonic condition. We have recorded and rotationally analysed the 0-0, 1-0, 2-0 and 3-0 bands. The rotationalconstants of the upper state A2∑- were determined and vibrational constants improved. In addition, the lifetimemeasurement for the A2∑- state was carried out under the collision-free condition, and the lifetimes obtained are469±2, 456±2, 488±3 and 490±4ns for v'=0, v'=1, v'=2 and v'=3 levels, respectively.