Abstract: Transportation pipes are widely used in liquid and gas transportation because of its special advantage, but the accident of pipeline leakage comes up frequently because of the inevitable aging and rot of pipelines, which may cause loss of human lives and properties, and pollute environment. Therefore, the pipe inspection becomes an important way to prevent leakages. The optoelectronic detection technology has been used for in-pipe inspection successfully thanks to its visibility and huge information. Because the space inside a pipe is narrow, especially for small diameter pipes, the sensor miniaturization is critical in the optoelectronic detection techniques. Some kinds of optoelectronic techniques such as laser array, PSD detection, light ring section detection and structure light detection are introduced, and their principle and configuration are elaborated. Their characteristics are analyzed and compared.The analyzed result shows that the optoelectronic detection technology is applied to the inspection of in-pipe surfaces, and its development trends towards the fast recognition of defects, the accurate 3-D detection and 3-D image display of in-pipe surface blemishes.