The purposes of this study were to develop a qualitative problem-solving strategy and to examine the effect of using such a strategy to improve ninth-graders’ problem-solving ability in physics. We targeted to enhance the way students approach problems by helping them realize the importance of qualitative analysis while solving problems. In particular, students were instructed to solve problems by analyzing the problems with principles or concepts and specifying the relationship between principles and problems before they applied formulae. To evaluate the effect of this strategy, the perspective of Preparation for Future Learning (PFL) was adopted. Students were provided with problem-solving resources in their tasks. The aim of the study was to explore whether students could make good use of the qualitative problem-solving strategies learned in the classroom, thereby raising their awareness of the problem-solving resources and successfully solving the target problems. Students’ problem-solving ability was examined in three aspects: the use of problem-solving strategies, the reduction of problem-solving strategy defects, and the success rate of solving problems. Results indicated that the participants using a qualitative problem-solving strategy showed a significant improvement at learning progress and had better performances in comparison with a traditional problem-solving strategy.