Problem-posing has been regarded as a potential method to engage students in deeper thinking; however, without sufficient supports, most students could encounter difficulties in posing quality problems. In this study, a concept mapping-based online cooperative problem-posing (CM-OCPP) approach is proposed to guide students to complete problem-posing tasks in online collaborative learning contexts. To verify the effectiveness of the proposed approach, a quasi-experiment was conducted in a natural science class at a junior high school with two classes of seventh graders. Among them, one class with 29 students was assigned as the experimental group conducting the CM-OCPP approach; the other class with 29 students was the control group conducting the conventional online cooperative problem-posing (C-OCPP) approach. The research findings showed that the CM-OCPP group had better learning achievement, problem-solving skills, and problem-posing quality in terms of topic relevance and depth of questions than the C-OCPP group. The interactive pattern analysis results further showed that, with the guidance of the CM-OCPP approach, the students engaged more in knowledge sharing, discussion, knowledge co-construction, and diverse thinking.