Based on the practical experienceswe learned from“5·12”Wenchuan Earthquake reliefworks, the paper discusses some key technical issues on data acquisition and post-processing arising from the airborneLIDAR system when it is applied to rapid response. After briefly introducing the basic principles ofLIDAR technology and its post-data processing work flow, severalkey technical issues concerning data acquisition and processing are expounded: (1) Ssystem calibration, which is actually mi portant to all scenarioswhen LIDAR system is to be used; (2) Flightplanning, the first and is also the key step as forhigh accuracy data acquisition. A good flightplan is ofgreat mi portance, especially when LIDAR system works in hilly areaswith high relie,f where weather condition is often complicated aswel;l (3) Ground GPS base station setting up. GPS base station, which isnecessary ifPOS system is adopted and high positioning accuracy isdemanded. Several requirements should be satisfied; (4) Conditions forobservation, including topographical condition,weather condition and forestry covering, allofwhich can influence the accuracy of the final results; (5) The choice of LIDAR hardware systems.Though several commercial LDIAR systems can be selected, we should bear in mind that each system has its pros and cons. Observation conditionshave to be taken into consideration, especiallywhen theLIDAR sys-tem is to be used over the hilly areas, such as in Sichuan Province; (6) The choice of laserpoweremission. As an active sensor system, LIDAR emits power by itsel.f However, there is a lmi itation as howmuch power is emitted. When lower power is emitted, itmay lack ofenergy thatsignals can notbe reflected by ground objects, so no echoes recorded. On the other hand, if raising power emission to a very high leve,l it isharmful to the hardware components of the system. So the optmi al choice is amust.Some achievements using the Leica ALS50 second generation LIDAR system are listed in the latter section, which show the airborne LIDAR technology is an efficientand practicalway to obtain high accuracyDEM data forSouth-western China. Some conclusions are summarized in the last section, including: (1) LIDAR system can acquire raw data under complex topographic and badweather conditions;(2)LIDAR technology is the bestchoice foraccurate DEM data acquisition in hilly areaswith high reliefand heavy forest; (3) data post-processing is tmi e efficientand shows its satisfaction for rapid response applications. Theworks described in the paper is helpful to smi ilar natural hazard reliefworks, and the technical issues discussed in the paper can be referenced by other smi ilar projects.