We study exotic structure of medium heavy hypernuclei with core nuclei of Ar isotopes and Ca40. Particulary, the superdeformed (SD) states and the corresponding hypernuclei are calculated in the frame of the Skyrme Hartree-Fock (SHF) + BCS model together with a microscopic ΛN interaction. We found that the Λ separation energy of the ground state is larger than that of the SD state. The result is consistent with the antisymmetrized molecular dynamics (AMD) calculation, but inconsistent with that of relativistic mean field (RMF). The similarity between SHF and AMD and the difference of Λ separation energy between SHF and RMF both come from the density distribution in the core nuclei and the corresponding hypernuclei.