Abstract: A new monostatic microwave imaging method for 2D dielectric cylinder in time domain is proposed. In this method, finite difference time domain (FDTD)and integer differential evolution strategy are used as an appropriate electromagnetic solver and global optimization method. A coarse radius solution of the dielectric object is achieved with the analysis of the TM mode and TE mode near-field. And then, with this solution as an initial guess for integer differential evolution strategy, the optimization is used to obtain the accurate solution. The main advantage of this method is its single-illumination single-view approach. It is not like the traditional method to obtaining the total shape information by multi-illumination multi-view approach. Thereby, imaging requirements is reduced greatly. Performance of the proposed method is demonstrated and discussed from dielectric cylinder profile reconstruction cases.