Self-directed learning is an important and basic ability for college students to acquire knowledge, and it is a prerequisite for training students' ability of innovation and creativity. Based on structuralist teaching theory, a blended teaching mode with Rain-classroom platform is designed in the study. The Likert-based scale for self-learning questionnaire is used to measure students' self-directed learning level. The results show that students' academic performance has been significantly improved (P<0.05), and they highly approve and embrace this teaching mode. In particular, the ability of self-motivating (72.5%), self-learning (89.0%) and understanding (87.2%) have been improved. According to the factor analysis (KMO=0.86), the improvement in self-directed learning, self-control, and learning effectiveness are most outstanding. This blended teaching mode is proved tohave contribution to the culture of self-directed learning ability.