Discovery teaching is an active teaching method. It helps develop the quality of student's competencies. It is really important in teaching using math tools and means. Our research focuses on understanding the perspective of discovery teaching as well as referring to the construction of a teaching method of plane geometry extreme problems with the help of specific GeoGebra software at secondary school. By the method of theoretical research, investigation as well as descriptive statistical methods, we find that using GeoGebra software has a great impact on the learning of plane geometric extreme problems of students. Students are interested and active in lesson construction. Students examine, create new problems by themselves, verify and discover solutions. The study also shows that GeoGebra software helps predict and find solutions, especially plane geometric extreme problems with a one-variable function. In Vietnam, with the introduction of a new general education program in mathematics, the application of mathematical tools and means is now very important. GeoGebra software was introduced right in 6th grade to teach. Students were introduced in detail to the features of the software. Therefore, the research results have an important meaning in building a lesson in solving plane geometric extreme problems with the help of GeoGebra softwarec at secondary school. Our paper refers to the views of discovery teaching, the teaching process using GeoGebra software in plane geometric extreme problems and gives an example of discovery teaching that applies GeoGebra software in plane geometric extreme problems.