By analyzing meteorological elements of 80 meteorological stations in Gansu province from 1961 to 2010, we concluded that the warmer and drying in the northwest region was the basic features of modern climate changing. The results showed that the annual average temperature raised 0.29 ℃ per decade and temperature increased 1.4 ℃ during nearly half a century. The warmer years were in the period of from 1997 to 2008 within 48 years. Annual precipitation had been declining since 1961, and the turning point was in 1986, the average annual precipitation reduced by 20 to 40 mm during 1987 to 2008 than that in 1961 to 1986. We analyzed the relationship between the development of wheat stripe rust, potato epidemic, aphid, cotton bollworm and red mite and meteorological factors. We explored the impact of climate warmdrying on the safety of HIV strains overwinter and oversummer, breed generations, disease time, harmful region, area and degree. The five main harmful characteristics had been exposed. First, the kinds of pests increased and harmful range amplified. Second, the boundary line of overwinter moved northward and harmful degree increased. Third, the period of pest growth extended, the breed generations increased and pest population growth accelerated. Fourth, the viral disease increased and pandemic occurred easily. Last, the ecology system of host, parasite and natural enemy population changed and the pest produced rapidly. We also provided four countermeasures to adapt to climate warmerdrying. We should firstly build the assessment and early warning system for crop pest monitoring and firstrate service. Next, the new control model of plant diseases and pests should be set up to adapt to climate change. Then, we should adjust the plant structure by weather forecast and different climate model year. Lastly, we should make fining crop pests comprehensive and agricultural natural resources division and confirm the region of high plant disease risk and the spot of key prevention and control.