Jn this paper, a succession model of population sequence {xi} in ecosystem was established. Analyses in detail were made on four cases of the succession model of population sequence under different conditions between Ni-di/ Ki and Ni + 1 - d i + 1/K i + 1.The succession models were investigated systematically with one population and two populations in ecosystem. The theoretical base for the division of three periods was suggested, and some useful results were provided for eco-environmental construction and ...