In this thesis,we study how to use Contour Integral Method to solve Lorentz model.We discretize the model equation using Yee's grid and project the research question to desired eigenspace.However,the efficiency and accuracy depend on some parameters of this algorithm.By doing numerical experiments,we reveal how to adopt good parameters and solve many more eigenvalues when clustering happens.The results can be applied to count the density of states and is useful for engineering.Based on the easy parallel algorithm and this eigenvalue analysis,we can also show the band structure more efficiently..