This paper developed a 4 array transducers photoacoustic endoscopic probe, and based on this, a photoacoustic endoscopic imaging system was build. Phantom experimental imaging was carried out, and the capability of location for endoscopic probe was demonstrated via analyzing the absorption of the light on the 4 sensors position. The in vitro human normal tissues and early colorectal cancer tissues was imaged using photoacoustic endoscopic system. The statistical analysis of the light absorbtion intensity distribution on different position proved that the photoacoustic endoscopic system has the ability to distinguish human normal tissues and early colorectal cancer tissues. This technology is expected to improve the accuracy of early diagnosis of colorectal cancer and has the potential clinical application.