Photoacoustic imaging technique overcomes the strong scattering effects of light when transmitting in organisms by detecting the ultrasonic signals based on the photoacoustic effect, which avoids the limitations of low depth of traditional optical imaging and low contrast of acoustic imaging. This technique has potential applications in early cancer diagnosis and it can possibly become an effective method for tumor diagnosis, locating, staging and treating. The principle of photoacoustic imaging and the research status of its clinical applications in early cancer diagnosis and treatment at home and abroad are mainly described. The potential application of photoacoustic imaging technique in biological medicine is prospected, and its future development trend and limitations are also analyzed.