Mucuna bracteata is a Legume Cover Crop (LCC) which has many advantages compared to other LCC. The generative propagation of M. bracteata is very difficult because of the seed coat is hard and thick, so that it has a long dormancy period and low germination. Germination without seed treatment, the germination ability only 12% to 18.33%. The efforts are made to break the seed dormancy by soaking the seeds in the sulfuric acid (H 2 SO 4 ) to remove the lignin layer in the seed coat. The present study objective was to determine the appropriate concentration of H 2 SO 4 for breaking dormancy of M. bracteata seeds. This research was conducted at the Laboratory of the 3 rd Campus Andalas University, Dharmasraya, in April to June 2019 used a Completely Randomized Design (CRD) consisted of 3 treatments with 4 replications. The seed treatments were some concentrations of H 2 SO 4 namely 3%, 4%, and 5%. The observed variables were T 50 break dormancy period, germination ability, abnormal germination, dead seed, first count test, index value, and maximum growth potential. The observation data were analyzed by an F test at 5% level, followed by the Duncan's New Multiple Range Test (DNMRT) at a level of 5%. The results showed that soaking of M. bracteata seeds in H 2 SO 4 with a concentration of 3% was the best treatment, a T 50 value of 8.75 days after planting with a germination capacity of 78.50%.