We classify the possible torsion structures of rational elliptic curves over sextic number fields. Among these group structures, all groups except C3⊕C18 are known to appear as subgroups E(K)tors for some curve E/Q and field K. prove that if image mod 2 Galois representation E is not equal Borel subgroup GL2(Z/2Z), then can't contain C3⊕C18.