Abstract: A typical binary aqueous solution with positive surface tension-temperature gradientwas experimentally and numerically studied. In this present paper, the surface tension of a1-pentanol aqueous solution was found to grow with the increase of the temperature under specificconcentration and temperature range. To verify this special phenomenon, flow fields of the1-pentanol aqueous solution under different horizontal temperature gradients were visualized andmeasured in a rectangular cavity by means of PIV method. And an inverse Marangoni convectiondifferent from that in pure liquid layer was investigated. For comparison, a numerical simulationwas carried out to obtain the velocity distribution along the free surface of the 1-pentanol aqueoussolution layer under same horizontal temperature gradients. Both results obtained by theexperimental observation and numerical simulation were found to display similar tendency.