Microwave imaging device and method are provided, and the microwave imaging device includes a scan circuit, a reception circuit and an image generator. The scan circuit transmits a plurality of electromagnetic waves in a plurality of scan bands toward a target object. The scan bands are respectively corresponding to a plurality of biological tissues in the target object. The reception circuit receives the electromagnetic waves passing through the target object, and generates a plurality of energy values according to the received electromagnetic waves. The image generator looks up a plurality of gray level look-up tables by using the energy values to generate a plurality of gray level values, and generates a detection image corresponding to the biological tissues according to the gray level values.
