The ability to think critically is a basic competency that must be possessed by students. This study aims to determine the level of critical thinking skills of junior high school students in Bima Regency, West Nusa Tenggara, Indonesia. Various studies have been carried out that explain how important students' critical thinking skills are, but there have not been too many studies on efforts to develop and empower students' critical thinking skills in a practical way. In this thesis, we introduce the technique of empowering students' critical thinking skills by developing a virtual laboratory media based on problem based learning on the material of the human excretory system. In this development, use software construct2 to develop a device which is then integrated with a problem based learning model. It is proven that a virtual laboratory based on problem based learning can improve the critical thinking skills of junior high school students in Belo Kaputen Bima District. We hope that the development of PBL-based virtual laboratory media can improve dramatically, such as the use of 3-dimensional and 4-dimensional software to improve students' understanding of critical and constructive thinking without losing quality.