The effects of the experimental conditions (integration delay, laser energy and so on) on the strength of metal LIBS (laser-induced breakdown spectroscopy) spectra are investigated using a self-developed new liquid jet by LIBS. The plasma emission spectra of K2Cr2O7, Pb(NO3) and CdBr2 aqueous solutions at 532 nm laser excitation is obtained. And the characteristic spectral lines of toxic metals Cr, Pb and Cd are identified. It is found that the detection limits of Cr, Pb and Cd are respectively about 0.32, 15.6 and 57.6 mg/L. The results unfold the rapid detection capability of the liquid jet by LIBS on toixc metal in water.