The nonlinear singularly perturbed problem is an important object of study in the international academic circles. It deals with many subjects. On the study of certain ecological phenomena, an original research adopts only some simple observational and statistical date to obtain the conclusion. But it cannot validly reflect its essence of the ecological phenomenon. Recently, the research some method of dynamics is produced for the study of ecology in international academic circles, i. e. the people first reduce it to the differential equation of model，which reflect its essential phenomenon and then solve the solution of the corresponding equation with mathematic methods; finally, study its dynamic rules upon the theory of biology and mathematics. Lately, the nonlinear perturbed problem has been widely investigated. Many scholars have considered the approximate theory. Approximate methods have been developed, including the method of averaging, boundary layer method, methods of matched asymptotic expansion and multiple scales and so on. This paper deal with the nonlinear generalized Lotke-Volterra prey-predator ecological model. A perturbation method, being simple and valid, is applied to study the prey-predator ecological model. The authors first provides a model of the prey-predator model, which is a system of differential equation and has developed the undermined functions in power series as small positive parameter. Then the equations of the coefficients for power series are obtained. And their solution is solved. Thus using the perturbation method the asymptotic expansions of solution for the original problem are obtained. The conclusion is that a good approximation for the original model comes to a solution, which is an analytic expression, and can keep on analytic operation. Lastly, a corresponding example is given, which show that obtained solution possesses a very good accuracy.