In order to improve the limit of detection and linearity without losing the advantage of on-line and in-situ measurement, laser-induced breakdown spectroscopy assisted by nebulizer is investigated. The influences of the main experimental parameters, namely the defocusing amount, the distance between the nebulizer and the central of laser beam, the ablation energy and the delay are studied to maximize the signal-to-noise ratio. Using laser-induced breakdown spectroscopy assisted by nebulizer, we demonstrate that the detection limits are 1.2, 3.2, 19.1, 3.4, 2.8, and 15.9 ppm for Ca, Cr, K, Mg, Na, Pb respectively, and the linearities are all above 0.99. The results show that laser-induced breakdown spectroscopy assisted by nebulizer is an effective method to detect the tracing metal element in liquid on-line and in-situ.