With the development of photoacoustic spectroscopy, non-invasive photoacoustic imaging technology based on the photoacoustic effect is gradually becoming a research hotspot in biomedical applications. This technology combines the benefits of optical imaging with the advantages of acoustic depth propagation, allowing it to break through the optical diffraction limit and scattering limit while maintaining a high imaging resolution. This article first introduces the principal mechanism of photoacoustic imaging and then introduces the three typical photoacoustic imaging technologies: photoacoustic computed tomography, photoacoustic microscopy and photoacoustic endoscopy. Furthermore, the benefits of these three imaging technologies are compared, and the various methods to improve imaging resolution over the last ten years are summarized. Finally, the future development trend of the three technologies is forecasted.Photoacoustic tomography was the first photoacoustic imaging technique to be developed. Traditional medical tomography plays an important role in diagnosing diseases, but that is not completely safe due to the presence of radiation that can cause some damage to the human body. Photoacoustic tomography is one of the safe imaging methods based on the photoacoustic effect that is radiation-free. Since the 1990 s, photoacoustic computed tomography has made significant progress. Researchers have improved the imaging resolution and imaging reconstruction speed of photoacoustic computed tomography by increasing the number of ultrasound transducers and improving the accuracy of the algorithm. This technology has achieved many excellent results in human breast cancer detection.The advantage of photoacoustic microscopy is that it has a higher imaging resolution at the same penetration depth than the photoacoustic computed tomography system. The photoacoustic signals of photoacoustic microscopy systems are generated at the point where the light and acoustic focal points overlap, so, photoacoustic microscopy systems are usually divided into two categories based on the type of focal point: acoustic-resolution photoacoustic microscopy (AR-PAM) and optical-resolution photoacoustic microscopy (OR-PAM). Researchers are particularly interested in the study of optical resolution photoacoustic microscopy because it can obtain high-resolution imaging results at the subcellular, cell, and tissue levels while allowing for non-invasive detection in vivo and can also be miniaturized under certain conditions for more suitable application in clinical detection technology. In 2005, WANG Lihong designed the first dark-field reflective photoacoustic microscope, and then photoacoustic microscopy technology officially entered the biomedical field. In the last few years, this type of imaging system has made a lot of substantial progress through continuous research on the optical path part, scanning part, and signal receiving part.To image deeper internal tissues and organs, researchers have combined the mature optical endoscopy approach with photoacoustic effects to create photoacoustic endoscopy. In 2009, WANG Lihong was the first to report a rotary mechanical scanning system with built-in optical excitation and micromotor acoustic detection and establish the concept of photoacoustic endoscopy. This method has been continuously improved and optimized by the researchers.The future development of photoacoustic imaging technology will be toward imaging results with high resolution, high timeliness, and high accuracy. Instrumentation will become real-time, small, practical, low-cost, and gradually mature.