Abstract: Activated carbon fiber(ACF) was successfully introduced as adsorbing material of SPE for the pre-concentration of micro organophosphorus pesticides(OPs) in water sample.Various factors,such as ACF weight,eluent type,OPs initial mass concentration in water,sample flow rate and pH have been tested,among which eluent type and ACF weight were significant ones to affect SPE recovery rates.The optimum condition is that for 1 liter of waters spiked with OPs(mass concentration 0.1 μg/L)from different sources,0.2 g ACF and 8 mL dichloromethane are needed,water flow rate is 40 mL/min, obtaining extraction recovery rates ranging from 80.7% to 118%.The pH did not apparently affect extraction recovery rate.