【Objective】Nutrient release during the decomposition of organic materials in soils is an important process in the nutrient element biogeochemical cycle, which could be used as substitute for chemical fertilizer. It is a fundamental to build the best straw returning practices to know the coupling characteristics and mechanism for nutrient release during straw decomposition under different climate and soil conditions.【Method】In this study, we transplanted neutral black soil (Phaeozem), alkaline chao soil (Cambisol) and acidic red soil (Acrisol) in cold-temperate, warm-temperate and mid-subtropical zones, respectively and setup the Soil Reciprocal Transplant Experiment. Wheat and maize straws were packed in 200-mesh nylon bags and buried at the depth of 10~20 cm in three types of soils in parallel in three climate regions, and then sampled at 0.5-, 1-, 2- and 3-years of decomposition. The effects of climate, soil and straw condition on nitrogen (N), phosphorus (P) and potassium (K) release associated with the decomposition were examined.【Result】The results showed similar releasing patterns for nitrogen and phosphorus. In cold temperature zone, the N and P nutrients released in the pattern of an enrichment stage followed by a release stage, while in warm temperature and subtropical zones they showed a continuously release pattern. The N and P released directly in Phaeozem but enriched firstly then released in Cambisol and Acrisol. The K were released directly during the 3-year decomposition, and the mean K release rate (FtK, percentage of total K in wheat straw or maize stalk residue to that in the straw applied) amounted to 89.5%1.1% in the first half year. During the 3-year decomposition, the nutrient release rate decreased followed the sequence of K>P≈N. Climate conditions contributed to 19.55.3% and 19.55.0% of variation for N and P release amount, while soil conditions to 16.66.5% and 13.87.0%, respectively. Meanwhile the contribution of climate and soil conditions to the variation of nitrogen and phosphorus release amount decreased with the decomposition going on. The K release was significantly but slightly affected by the straw conditions which contributed to only about 2.230.07% of variation. Among the interaction effect of these factors, the climate × straw and soil × straw affected significantly the N and P release amount. At later decomposition stages (2-3 years of decomposition), the total contribution of all factors (climate, soil and straw) to the variation of the nutrient release was less than 30%, which suggested that the other environmental factors, especially the biological factor, may play an important role during the process of nutrient releasing. The stepwise regression equations between nutrient release rate and climate, soil and straw factors were Yt _N= -3.41 -0.40C/N +0.49TN +0.43AT (R²=0.67, p=0.001), Yt_P= -83.73 +0.49RH +0.42TN +0.25N/P (R²= 0.47, p=0.003), and Yt_K= 2 574.39 -0.87C/N -0.33N/P -0.30RH (R²=0.62, p=0.002) for N, P and K, respectively. In which, AT stands for annual mean temperature; RH for relative humidity; C/N for carbon/nitrogen in straw; TN for soil total nitrogen content; N/P for nitrogen/phosphorus in straw.【Conclusion】In general, during the 3-year decomposition of wheat and maize straw under different climate and soil conditions, the N and P were released mainly in the pattern of an enrichment stage followed by a release stage, or in a continuously release pattern. However, the K was released all in a direct and faster pattern. The climate and soil conditions are the main controlling factors for N and P release, while the straw quality was the main factor influencing the K release.