The form invariance of general Chaplygin system was studied. Using the infinitesimal transformations of general Chaplygin equation, the definition and criterion of the form invariance of general Chaplygin system were given. The criterion of Noether symmetry of general Chaplygin system was given, and the relation between the form invariance and the Noether symmetry was studied. The results show that the form invariance of general Chaplygin system isn't identical with Noether symmetry. In some situation, the form invariance may be equal to the Noether symmetry, and in another instance they are different. One example was given to illustrate the application of the result.