Natural gas pipeline leak detection is significant in terms of security, environmental protection and security of state property. however, the leak detection is difficult, because of the pipeline's covering many areas, operating conditions and coplicated environment. quantitative remote sensing of natural gas leakage and location research, with laser absorption spectroscopy, will be faster, safer, more accurate and intelligent. this standoff scanned-wavelength differential absorption spectroscopy (SWDAS) sensor is enabling novel applications for remote gas sensing and non-contact process monitoring. SWDAS is feasible and applicable in natural gas leak detection by analysing the experimental results,which will become a new diagnostic method for leak detection.