The laser-induced fluorescence excitation spectrum of jet-cooled NiF in the 17500-25000 cm(-1) region has been recorded and analyzed, in which the NiF molecule was produced by the reaction of the sputtered nickel atoms with SF6 under discharge conditions. Numerous bands are observed, With the help of the isotopic shift measurements and vibrational constants determined by B. Pinchemel's group, 26 bands have been vibrationally assigned. Twelve rotationally resolved transitions were found to originate from the ground state and terminate in different vibrational levels of four electronic states, [18.1] (2)Delta (5/2), [20.0] (2)Delta (5/2), [20.3] Omega = 3/2, and [22.9] (2)Pi (i), respectively. The molecular constants of these four upper states are determined. In addition, lifetime measurements of the four excited states were carried out under collision-free conditions. On the basis of the spectroscopic data and lifetime measurements, the electronic structure and interactions of these high-lying electronic states are discussed.