Three new diterpenes, caesalmin U (1), caesalmin V (2) and caesalmin W (3), were isolated from the EtOAc extract of the seeds of Caesalpinia minax Hance. Their structures were mainly characterized on the basis of extensive spectroscopic analyses and comparison with reported data. The inhibitory activities of nitric oxide(NO) production release of RAW 264.7 cells stimulated by lipopolysaccharide (LPS) of compounds 1-3 were evaluated, and compound 1 displayed moderate activity with IC50 value of 23.72 μM.