In　order　to　enhance　heat　transfer　and　control　a　thermal　effect　effectively,　an　optimal　design　of　a　flat　shape　of　a　minitype　gas　tank　for　vehicles　was　done.　The　results　of　the　numerical　simulation　are　drawn　within　the　gas　tank.　Added　heat　exchange　tubes　are　able　to　make　the　heterogeneity　of　temperature　distribution　reduced　by　about　60%;　Added　fins　later　can　reinforce　the　gas　tank　structure　and　raise　the　ability　of　a　gas　tank.　The　heterogeneity　of　temperature　distribution　goes　down　further.