We theoretically and numerically investigate the ratchetlike motion in a dimer bouncing on a vertically oscillating plate.A correlative coefficient associated with the static coefficient of friction μs and the aspect ratio Ar is found responsible for the transport mechanism of the drift behaviors in the dimer.A few numerical simulations exhibit precise agreements with the experimental findings presented in [9].Furthermore.an approximate formula for the mean speed of the net horizontal motion is deduced in this letter.