With the rapid development of economy, China's tunnel traffic construction has also made significant progress, and the number and scale of operating tunnels have increased significantly. Therefore, the daily inspection of tunnels in operation has become a concern. The current tunnel disease detection methods are mainly divided into non-destructive testing and damage detection, and damage detection affects the service life of the tunnel, so the current main detection method is non-destructive testing. In this paper, through the collation and analysis of the tunnel nondestructive testing related literature, mainly introduces the geological radar which is widely used and the three-dimensional laser scanning which is more promising. Firstly, the development and application of GPR in tunnel engineering at home and abroad are introduced, the problems existing in practical engineering are analyzed, and corresponding suggestions are put forward. Secondly, the basic principle and common equipment of 3D laser scanning are introduced, and the application of some tunnel detection at home and abroad is analyzed. Finally, a summary of the issues encountered by the two tunnel detection technologies during the detection process is provided, followed by the proposal of practical solutions. It has been observed that the utilization of a single technology for detecting tunnel deformations and lining surface conditions, or limiting the analysis to the thickness of tunnel lining and the non-compactness behind the lining, fails to enable a quantitative evaluation of the tunnel's operational health, and the economical and practical maintenance of the tunnel cannot be accomplished. Therefore, the joint use of multiple tunnel detection instruments will become a new trend, while the combined use of geological radar and three-dimensional laser scanning will consider both inside and outside. It is a development direction of tunnel detection technology.