Ultrasound/photoacoustic dual-modality imaging technology has greatly promoted the clinical application and promotion of photoacoustic imaging technology because it combines the advantages of high-resolution structural imaging of ultrasound and high-contrast functional imaging of photoacoustic imaging. Traditional ultrasound/photoacoustic dual-modality imaging is mainly based on the array probe used in ultrasound imaging to collect photoacoustic signals at the same time. The system has a compact structure and easy operation. However, this kind of equipment utilizes array probes and multi-channel data acquisition system, which makes its expensive. And the imaging quality can be affected by the difference of channel consistency. In this paper, an ultrasound/photoacoustic dual-modality imaging method based on an acoustic scanning galvanometer is proposed. In this system, a single ultrasonic transducer combined with a one-dimensional acoustic scanning galvanometer is used for fast acoustic beam scanning to realize ultrasound/photoacoustic dual-modality imaging. It is a compact，low-cost and fast dual-modality imaging technology. The experimental results show that the effective imaging area of the system is 15.6 mm, and the temporal resolution of ultrasound and photoacoustic imaging is 1 and 0.1 B-scan /s, respectively (the temporal resolution of photoacoustic imaging is mainly limited by the laser repetition rate). Based on the proposed technology research, it is helpful to further promote the clinical transformation and popularization of ultrasound/photoacoustic dual-modality imaging. It also provides a low-cost, miniaturized and fast scheme for multimodal imaging technology which based on ultrasound signal detection.