Based on econometrics and meteorology, the meteorological factors have been introduced into the renowned economic CobbDouglas production function, yielding an integrated model using real data from 1978-2006. The concepts of elasticity and range rate are presented in this paper to evaluate the effects of weather conditions on agriculture economic output over China. The results show that, the rationality and scientificalness of the model have been verified as the inclusion of meteorological factors improves the overall fit of the traditional CD production function and the interannual variability of agriculture economic output can be simulated accurately. Compared with precipitation, temperature has greater and more significant impacts on agriculture economic output over China. The magnitudes of range rate are from 5% to 85% for 31 administrative regions and a range from 3.4% to 19.5% for eight geographical regions of China. Econometric model can quantitatively assess the socioeconomic impacts of weather and climate variability, provide a new approach for weather and climate change research and there will be a bright prospect for its application.