Abstract: A flow injection peroxide value of edible oil measuring method was established。A kind of flow injection measuring peroxide value of edible oil instrument was developed based on the flow injection analysis-spectrophotometric colorimetry,the electric three-channel flow valve and the constant flow micro-pump was developed.The flow direction of the carrier liquid was controlled by the valve,nine solution holes of three switches were on the same circumference of the valve body,occupying less space,three kinds of carrier fluid were changed direction at the same time by thirty degrees rotated by the valve body. the injection of a sample solution was controlled by the pump,the high-pressure solution was formed in the conical cavity by the propeller rotating,and the rotating without contact and friction,and the dead volume was small. The linear range for the concentration of peroxide value was from 5 to 170 μmol / L with a correlation coefficient of 0.9995,the limit of detection was3.57 μmol / L,the recovery rate was between 93% ~104%.This method is used for rapid detection of peroxide value of rapeseed oil,recycled oil and hot pot oil,the determination results of this method and national standard method for T-test analysis,testing results of two methods have no significant difference.