Abstract: This paper was aimed to set a simple and highly-efficient method for lactose adulteration detection in raw milk. After pretreatment using trichloroacetic acid as precipitant,at 589.30 ~589.44 nm,the optical rotation was measured by polarimeter to create standard curve about standard lactose solution. So as to establish a polarimetric method for quantitative detection of the lactose adulteration in raw milk based on standard curve.The correlation coefficent(R2) of this regression equation acquired in our study was equivalent to 0.9993;the average recovery rate was 99.0%;the relative standard deviation was 0.67%. In the comparison test,the results showed no significant difference between the Laing Henon 'method and the one established in this study,but the latter was simpler and cheaper than the former. It was suggested that such method was practical and reliable.