Microwave imaging is a promising method for the early-stage breast cancer detection. Recently, the reflection and scattering behaviors of the microwaves propagating in the breast have been widely simulated both in 2-dimensional and 3-dimensional configurations. In this paper, a method to create quasi 3-dimensional image from 2-dimensional simulation results by confocal algorithm is proposed. The basic investigation of electromagnetic field in the breast is carried out with a 2-dimensional simulation code. By moving the emitter-detector array to several parallel positions, the detected signals can be synthesized to form quasi 3-dimensional images.