The utility model discloses a plug -in hybrid vehicle's driving system is arranged to planet that efficiency is higher, the oil consumption is lower, its characterized in that: outer axle (5) is the hollow shaft, still includes second clutch (3), interior axle (10) to and second sun gear (11) be located planet carrier (13) within, second planet wheel (12) rotationally installs the second planet row on planet axle (131) of planet carrier (13), the outer drum of second clutch (3) and the outer drum of first clutch (4) connect firmly and are associative with the right -hand member of input shaft(2), the left and right end of interior axle (10) stretches out respectively in the left and right end of outer axle (5), and its right -hand member connects firmly with second sun gear (11), and itsleft end is associative with the interior hub of second clutch (3), first planet wheel (7) that first planet was arranged connect firmly, just control and install side by side on planet axle (131) with second planet row's second planet wheel (12).