Heavy metal element chromium in sewage solution is detected by laser induced breakdown spectroscopy (LIBS). The spectral lines of Cr element are obtained. The calibration curve of the line intensities versus the concentrations of Cr element is acquired by experiment. Atomic lines of CrⅡ(283.43 nm) and CrⅠ(425.45 nm) are analyzed and compared. The experimental results show that the intensity of atomic emission line of CrⅡ(283.43 nm) is three times as large as that of CrⅠ(425.45 nm). The linear correlation coefficient of calibration curve and signal-to-background ratio for CrⅡ(283.43 nm) are better than those of CrⅠ(425.45 nm). The LIBS detection limit of Cr in the solution is 80 μg/mL (283.43 nm) and 170 μg/mL (425.45 nm). The calibration curve for CrⅡ(283.43 nm) has been used for quantification of Cr in sewage solution, and the concentration of Cr is found to be 333 μg/mL. This result is compared with Cr concentration obtained by atomic absorption spectrometry (309 μg/mL), and a close agreement is found. This study indicates that the atomic line of CrⅡ(283.43 nm) is better than CrⅠ(425.45 nm) for LIBS detection. The LIBS technique can be applied in the rapid detection of Cr element in sewage and has good application prospects.