By using the reanalysis data of NCEP (1°×1°) , the dry intrusion characteristic of a strong dust storm p rocess occurred in the Hexi Corridor from Ap ril 9 to 10, 2006 was analyzed. The results show that the high potential vorticity, dry air from the upper level of troposphere extended downwards and southwards, which increased the vertical component of the vorticity on the steep iso - entropy p lane and p romoted the rap id development of the low level cyclone, resulted in a low level jet and the intensive convergence in the
boundary layer.

Based on C + + BUILDER 6. 0 software exploiting tool，the Sandstorm Information Collection and Transmission System was built. The system can carry out transmission of sandstorm data and other meteorological information at regular time or in handwork by the interface with flexible parameter settings under windows operation system. The software compiling of second transmission of information under SCO UNIX operation system was finished，it can transmit sandstorm data and other information from provincial meteorological bureau to Chinese Meteorological Administration（CMA），especially it can transmit long - name files，which resolved the problem in 9210 Operation Applying Software（national meteorological information transmission software in China）

In this paper, the distribution, causes and characteristics of geological calamity in Lanzhou city were analyzed, and the temporal and spatial distribution of geological calamity and intense rainstorm, the weather systems and the relation between geological calamity and rainstorm intensity were studied mainly. The critical precipitation index were set up and defending countermeasure was given, and these will he necessary for developing prediction and warning of geological calamity in Lanzhou city.