The present paper deals with the relationship between the soil nitrogen supply and the rice yield.The pot experiment of late rice on four representative paddy suits in Zhejiang province,namely,the Bluish gray clayey soil (a stagnogley paddy soil),the Red Brume soil (a percogenic paddy soil),the Rust mottled clayey soil and the Cray clay loamy soil (periodical submergic paddy soil) was carried out with the fertilizer labelled by ¹⁵N.The vreliminarv results are summarized as follows:(1) The rice plants on the more fertile soil,such as the bluish gray clayey soil,absorbed more soil nitrogen se 1.3 times than that on the gray clay loamy soil with a lower fertility.Therefore,it seems that the fertility of soil may be considered as a very important factor which would significantly affects the absorption of the soil nitrogeh by rice plant.