Abstract: By using the numerical method, this paper investigates the probability distribution of a particle moving in the one-dimensional square barrier for three cases： E〉Uo ,0〈E〈U0 and E= U0. We give the probability density figure where the probability distribution evolution in scattering processes in different square barriers can be clearly seen. The relation between the transmissions, reflection coefficients with the barrier height has been ana- lyzed in detail.

Key words: probability distribution, square potential barrier