In the present study,a spectrophotometry method for the simultaneous determination of gibberellins (GA3) and glyphosate in groundwater was established and optimized.In addition,the mutual effect on simultaneous determination of GA3 and glyphosate was studied.Based on the experiment,good linearity (R2>0.99) was obtained for GA3 in the range of 0~20 and 0~100 μg and for glyphosate in the range of 0~8 and 5~15 μg.The method's detection limit (MDL) of GA3 and glyphosate was 0.48 and 0.82 μg,respectively;and the recovery rates of 15 to 150 μg GA3 and 3 to 10 μg glyphosate in all samples at a spiked level were 71.3%±1.9% and 98.4%±8.1%,respectively.No obvious influence of glyphosate (0～100 mg·L-1) on the recovery rates of GA3 was observed,but the presence of glyphosate could cause slight determination precision decrease of GA3.Meanwhile,adding 2 mg·L-1 GA3 can increase the recovery rate of glyphosate.