Abstract:In field experiment the changes of classification of source and sink were studied with rice, Xiu Za and other varieties (combination) under different cultivation condition.The results showed that the classification of varieties for source and sink changed when nitrogen supplies, the ways of seedling transplant and the numbers of transplanted seedlings. per pit differed, of which nitrogen supply affeeted the changes greatly. No matter what a classification of source and sink of varieties in intermediate level of fertilities was, most varieties appeared the source-sink-harmonic type when grown in the condition of low fertilities, and tended to be the source-limited type in the high fertile condition. The influence of transplanted seedlings per pit on the change of source and sink were similar to fertility effeet. When the numbers of the transplanted seedlings were less it was equal to low fertilities and when they were excessive, similar to high fertilities. The effects of the way of transplant seedlings were different to changeof classification between source and sink of varieties. In this paper. The reasons for the changed relation between source and sink of varieties in different condition were also discussed.