A sand trap for collecting creeping sand was designed to avoid collapse of sand on the leading edge of sand tank. Then wind tunnel experiments were conducted to analyze the impacts of height and thickness of the trap on the creep-sediment-transport rate, and the effective height and thickness of the sand trap was given out. By means of this kind of sand trap, the creep-sediment-transport rate was measured at different wind velocities. Finally the threshold wind velocity was extrapolated.