The laser-induced breakdown spectroscopy (LIBS) technique has been successfully employed for qualitative and semi-quantitative elemental analysis of trace heavy metal element in solid samples and gas samples. To make an analysis of the heavy metal trace element in liquid, the LIBS of the AlCl3 solution was measured with the single pulse LIBS technique applied flexibly in experiment. The time revolution properties of the Al LIBS signal in the solution, the dependence of the LIBS signal on the laser energy, and the detection limit of the LIBS technique were also investigated. The experimental result showed that the laser energy suitable for this experiment is approximately 50 mJ and lower than that reported in previous experiments. With this easy realizable experiment, a higher detection limit of the LIBS in liquid samples was obtained. The result also showed that there are peculiar time revolution properties of the LIBS signal in liquid. The lifetime of LIBS signal in liquid samples was shorter than that in solid samples, about 30 ns. Meanwhile, the LIBS signal intensity increased and decreased quickly, only lasting several ns.