Any regional climate resource is regarded as a kind of climate state vector from the view of climate vector, by means of rotating principal component analysis, the state vector of climate resources is calculated, on the basis of which, the light resource, heat resource, moisture， and other climatic and environmental conditions are integrated as the vector of climate resource. A comparative relationship with a crop growth model of the standard curve is established, and then one new model about the production potential of agroclimatic is put forward. Relative photosynthesis production potential, photothermal production potential，and climate production potential have been obtained, all of which prove the limitations of the classic method. The tests show that this improved relative production potential has better universality and comparability, which is suitable for comparing the crop production in different areas.