This paper presents an approach for building a multi-classifier system in a Mean Field Genetic Algorithm (MGA)-based inductive learning environment. Multiple base classifiers are combined to build a multi-classifier system. A base classifier consists of a general classifier and a meta-classifier. The general classifier performs regular classification task. The meta-classifier evaluates classification result of its general classifier and decides whether the base classifier participates into a final decision-making process or not. MGA is a hybrid algorithm of Mean Field Annealing (MFA) and Simulated annealinglike Genetic Algorithm (SGA). It combines benefit of rapid convergence property of MFA and effective genetic operations of SGA.