In order to solve problem that not easy to be determined in natural uneven-age forest, taking the Richard equation as the foundation model, by derivation, the paper used site quality class as the dependent variables and plastochron as the independent to constructe stand yield model. According to the value characteristic of dummy variables, the immune evolutionary algorithm was introduced to estimate model parameters. The fitting was better, and it passed through the application test. On this basis, the paper used forest stand data illustrate the use of models, calculated stand biomass under different plastochrone and site quality class, analyzed the changes in forest carbon sequestration, had estimated the value potential of carbon sequestration under the different site quality class according to the formula of carbon sequestration value. All those were done to provide technical support for the formulation of national energy-saving emission reduction policies and responsing to climate change and environmental monitoring.