Through the mechanism analysis of simple genetic algorithm (SGA), every genetic operator can be considered as a linear function. So some disadvantages of SGA may be solved if the genetic operators are modified to a nonlinear function. According to the above method, a nonlinear genetic algorithm is introduced. By analysing of the concept of the schema, a new schema theorem is proved. The above work establishes a completely new mathematical analytic method of the genetic algorithms schema theory and contributes much to perfection and development of the theory of genetic algorithm.