According to the difficulties of learning the object-oriented concept of Java language for beginners, the paper mainly discuss the understanding and using of object-oriented respectively through three methods. The first method is to create an object through a no-parameter constructor, and then assign the object through a variety of ways. The second method is to create and initialize objects by parameterized constructor. The third method is same to the first method when creating objects, but their assignment methods are different. Choose which one method or combined methods, according to the specific situation of specific analysis. The experiments have proved that the comprehensive application and comparison of the above three methods can greatly improve the students' ability to understand object-oriented.