In this paper, an efficient optimization algorithm for solving the TE wave imaging problem of a two-dimensional homogeneous dielectric object is investigated. The problem of reconstructing both the shape and the relative permittivity of the cylinder from the measurement of scattered fields is numerically simulated. A homogeneous dielectric cylinder of unknown permittivity scatters the incident plane wave whose electric field vector perpendicular to z-axis (TE polarization) in free space and the scattered fields are recorded. Based on the boundary condition and the incident field, a set of nonlinear surface integral equations is derived. The imaging problem is reformulated into an optimization problem and the steady-state genetic algorithm is employed to reconstruct the shape and the dielectric constant of the object. Numerical results show that the permittivity of the cylinders can be successfully reconstructed even when the permittivity is fairly large.