Abstract: The population age structure and sexual ratio of wild black bear (Selenarctors thibetanus) were studied,and the static life-span table of black bear population was comfilead,and the innate capacity of increase was analysed.The results showed the mean life span of black bear is 6.366 years,the net reproductive rate (R0) is 1.69325,the mean time of per generation (T) is 11.544 years,the innate rate of increase (rm) is 0.04552857,and the finite rate increase (x) is 1.0466110.All these results based on the skull specimens of black bear,and combined with the data of age structure and reproduction and death of black bears which have been collected in domesticated population,and with mathematical analysis way.