A system and an imaging method for using photoacoustic effect are provided in the present invention. The system includes a light source for generating a light beam, a wave-guide probe and an ultrasound receiving device. The wave-guide probe further has a reception portion and at least one transmission portion. The reception portion receives the light beam and then triggers a photoacoustic effect inside the reception portion so as thereby to generate at least one sound wave thereinside to be further transmitted to the at least one transmission portion. The transmission portion is merged into the organic medium. When the sound wave is transmitted to the transmission portion, an ultrasound area is generated inside the organic medium. The ultrasound receiving device is located adjacent to the organic medium, receives the ultrasound generated in the ultrasound area to form an ultrasound image of the organic medium, so as to achieve the imaging method.
