The invention discloses grade 240MPa bake hardening steel and a manufacture method for the same. The grade 240MPa bake hardening steel comprises chemical components including, by mass, 0.0015%-0.0030%of C, no more than 0.03% of Si, 0.40%-0.6% of Mn, 0.05%-0.065% of P, no more than 0.01% of S, 0.02%-0.06% of Alt, 0.06%-0.014% of Nb, 0.0003%-0.0008% of B, no more than 0.004% of N as well as Fe andunavoidable impurities. The manufacture method comprises the steps that a steel billet is smelted at first; and then the steel billet is processed successively with hot rolling, cold rolling, annealing and galvanization. Finished steel manufactured with the method disclosed by the invention is characterized in that temperature sensitivity of the bake hardening steel is weakened; anti-aging time isincreased to over six months under a storage temperature of -10 DEG C-40 DEG C; and a yield point ductility rate Ae is not more than 0.8% before stamping.