ing at the demand of in-situ online monitoring of heavy metals in industrial wastewater, a continuous online determination method of heavy metals in water based on laser-induced breakdown spectroscopy (LIBS) is proposed. We adopt the enrichment type of graphite substrate evaporation to realize rapid and automatic detection of heavy metal elements in water by studying the enrichment mode of sample solution, method for quantitative addition of sample solution, and evaporation and enrichment type of sample solution, which can improve detection efficiency and capacity. The standard solutions with different mass concentrations of six heavy metal elements including Cd, Cr, Cu, Ni, Pb, and Zn are tested to establish the calibration curves and obtain the corresponding detection limits. The relative standard deviations of multiple measurements of spectral intensity are 9.24%, 10.45%, 12.59%, 11.58%, 15.24%, and 6.87%, respectively. The detection limits are 0.03, 0.012, 0.0047, 0.033, 0.071, and 0.0376 mg/L, respectively. The proposed method provides an effective measure for online monitoring of heavy metals in water.