Based on NCEP/NCAR reanalysis data and a self-defined storm track longitude index (I_X), a synthetic analysis was made to conduct an investigation on zonal variability of Atlantic storm track (AST) and its energy budget difference during boreal winters of the past 63 years (1948-2010). Results show that (1) the AST swings markedly in the east-west direction. When it expands eastward, the synoptic transient waves extend from Atlantic to Asia over the east of the Ural in the sky; while it retreats westward, the synoptic transient waves draw back to the west of 15° W over the ocean. (2) The energy budget analysis shows that the remarkable increase of the eddy kinetic energy over eastern Atlantic and western Europe at high latitudes corresponds to the eastern enlargement of the storm track. The intensification of eddy kinetic energy in the west of 0° is largely attributed to the strengthening of barotropic conversion, while in the east of 0°, the "downstream development effect" caused by the eddy ageostrophic geopotential fluxes may play the most crucial role. Vice versa while the AST retreats.