Abstract: Cold-rolled high strength steel contains many alloying elements, such as Mn, Si, Al. In the reductive atmosphere of annealing furnace, alloy elements are easier to oxidize than iron elements, forming oxidative enrichment on the surface or sub-surface of strip. Oxides of alloy elements are often distributed near grain boundaries in the form of oxide particles. In order to study the effect of different dew point and humidifying position of annealing furnace on the oxidation behavior of alloy elements on strip surface, hot-dip galvanizing simulator was used to simulate the working conditions of annealing furnace of production line. Under the condition of low dew point, it is easy to form oxidative enrichment of Mn element on the surface of strip steel and form coarse oxide particles, which may cause adverse effects on the surface quality of strip steel.By controlling dew point in appropriate temperature range, the enrichment and oxidation behavior of alloy elements on strip surface can be effectively improved, and the surface quality of strip can be effectively improved.