Based on the observations from 6 stations in Hami,climate features and synoptic situation of sandy and dust weather in last 40 years (1961—2000) are studied with the Surface Data Multifunctional Application System (SDMAS). The result shows that sandy and dust weather in Hami is composed of dust with a highest percentage of 61.6%,sandstorm (22.1%) and floating dust (16.3%). Such weather is most likely to happen in spring,then in summer and least in winter. It was a high frequency period for sandy and dust weather from 1960s to 1970s,and obviously decreased from 1983 to 2000. The sandy and dust weather usually happens from 15 to 21 p.m. and mostly concentrates during noon to afternoon,it is possible to happen when the wind speed is higher than 3.4m·s^-1,the precipitation will help to restrain the sandy weather. It is found that the sand storm mainly happens in 6 kinds of favorable synoptic situation.