Abstract: In order to study the effects of tillage time on decomposition and nutrient release of Dongmu 70, the mesh bag method was used in tobacco fields with two treatments of tillage time. The green manure was returned to the fields on March 23, 2016 (T1) and April 23, 2016 (T2), respectively. The samples were collected after 12, 25, 36, 49 and 61 d. The residual decomposition rate, N, P, K, C contents and their accumulation coefficients of Dongmu70 were investigated. The results showed that tillage time affected the residual decomposition rate of Dongmu70 with the slower decomposition rate of T2 and the higher decomposition rate of T1. In the end of the experiment, the residual decomposition rates of T1 and T2 treatments were 10.98% and 25.33%, respectively, For T1 and T2 treatments, the total contents of nitrogen, phosphorus and potassium were 0.76% and 2.87%, 1.52% and 1.42%, 0.44% and 0.33%, respectively. The accumulation coefficient of nitrogen for T2 treatment increased from 0 d to 12 d and reduced after 12 d. The others accumulation coefficients were continuously reduced. After 61 d the nitrogen, phosphorus, potassium and carbon accumulation coefficients of the two treatments were 0.02 and 0.53, 0.13 and 0.28, 0.02 and 0.03, 0.07 and 0.21, respectively. The test results showed that for T1 treatment green manure is easy to decompose, easy to release nutrients.