Abstract: A fast accurate determination of CS and OC by UV spectrophotometry was presented. 300 nm and 281 nm were selected as the detection wavelength of o-chlorobenzamalononitrile and nonivamide, respectively. Then the quantitative analysis of the stimulating components was realized by external standard method, and the accuracy and reliablility of this method was satisfactory compared with that of the HPLC method. Results show good linearity in the range of 0.1~25.0 μg·mL^-1 (CS) and 1~200 μg·mL^-1 (OC) with correlation coefficient 0.999 9, and detection limits were 0.02 μg·mL^-1 (CS) and 0.16 μg·mL^-1 (OC).The average recovery were 97.37% and 102.51% with the RSD being 1.04% and 0.64% respectively. The result indicated that the established method is simple, quick, and low-cost, which can be applied to determination of irritant agents in lachrymator.