With the isospin-dependent Nilsson potential, we calculate the properties of the N=28 nuclei in the framework of macroscopic-microscopic model. The shape and shape coexistence of these nuclei are calculated and discusses. It is shown that strong shape coexistences occur in the ground state of nuclei with N=28 in Na, Mg and Al isotopes. It is pointed out that, the ground state of 42Si is oblate shape and there is no obvious shape coexistence for 42Si.