Problem-Based Learning (PBL) is an instruction method which embodies the opinions of constructivists. It comes into being in mid-20th century at the request of the reform in medical education. Despite various interpretations of this concept, PBL is virtually characterized by problem-centered learning in group and students' self-determination. The comprehension of "problem" will reach a better understanding of pedagogical ideology of this method. The whole PBL flow subsumes five phases: (1) designing of problems, (2) presenting /encountering problems, (3) self-directed learning, (4) attempting to solve problems with new knowledge, (5) summarizing, reflecting, and evaluating learning processes. PBL is calling upon instructors' new role. There have been controversies over the effects of PBL on the quality of knowledge acquisition, but it is admitted that this method can enhance learning motivation, higher order thinking, the ability to gain and apply knowledge, and skills of social interaction. Taking students of grade one in junior middle school as subjects, the paper discusses how to apply Problem-Based Learning to composition instruction and the effect of this research. This research found that:1. PBL exerted a significant effect on enhancing the achievement of the students of junior one.2. PBL brought about significant gender differences in the effect size of PBL.3. The effect size of PBL is relative to the students' attitude to composition before the training in this research. |