The influence of the interference of electron waves in the case of their reflection from potential barrier on the inhomogeneous spatial distribution of the probability current density jx (x, z) (or a quantum-mechanical current density ejx (x, z), e is the electron charge) in 2D semiconductor nanostructure which is represented by rectangular narrow (x < 0, QW1) and wide (x > 0, QW2) quantum wells (QWs) sequentially oriented along the direction of the propagation of electron wave has been studied theoretically. We investigated behaviour of the ejx (x, z) at falling of the electron wave on rectangular semi-infinite potential barrier (a potential wall) in height V0 in semiconductor 2D nanostructure providing existence of the interference effects. We have considered a situation when in the 2D nanostructure at the left, from QW1 the electronic wave of unit amplitude with energy Ex < V0 on such barrier in QW2 falls.