The invention provides a high-speed detection system and method of tunnel defects. The system comprises a master control unit, a linear laser, an area array charge coupled device (CCD) camera, an image compression unit, a displacement sensor, a synchronous controller, an image storage unit, a storage module, a correction module and an inertial navigator. A special measurement locomotive serves as a mobile monitoring platform for the design and is particularly suitable for subway tunnel monitoring, and subway and other tunnel space structures can be effectively, rapidly and dynamically measured; the actually measured data is compared with actual real distance, errors are analyzed, the parameter setting is adjusted, and the measurement accuracy is greatly improved; moreover, the XYZ axial vibration of the mobile monitoring platform is subjected to error correction through the inertial navigator, and a measurement error is prevented from being introduced into mobile measurement.