The linear muffin tin orbitals method was adopted to calculate the band structures of the strained- superlattice (ZnS)1/(ZnSe)1(001) grown on the Si substrate.In our calculation the external adjusted potential was used to overcome the problem of too small a band gap in it.On the basis of relatively accurately calculated band structure and wave function for this system,we calculated the imaginary part of dieletric function of the superlattice system.The results showed that the optical properties of (ZnS)1/(ZnSe)1(001) grown on the Si substrate consisted of the optical properties of bulk ZnS and of bulk ZnSe,and they have rather good optical response over a wide range of photon energy;futhermore,the superlattices are direct band gap materials.Thus the superlattices will become the promising materials for optoelectronic device applications.