The characteristics of the switching and the self-trap of bright solitons in a BoseEinstein condensates （BEC） system of periodic or aperiodic traps are investigated and the evolution of the BEC solitons as time changes is discussed. The atom population transferring ratios among the three BECs as time changes are analyzed, and it is found that population transfer among the three BECs depends on sort of traps, and changes in a periodic or aperiodic manner as the time changes.