With the rapid advancement of education, personalized learning has gained considerable attention in recent years. Learning path plays an important role in this area and has attracted great concern. Many generating mechanisms have been proposed from different perspectives for assisting learning. Some methods focus on learners' interest, while some methods pay close attention to learning styles. This article proposes a new learning path generating method named learning diagnosis-learning path (LD-LP), which is based on knowledge structure and learning diagnosis. Different from the previous work, it takes knowledge relation, learner's ability, learning time, and repetition into account. The difficulty of knowledge provided to students will be adjusted according to students' academic achievement and learning time adaptively. The system generates personalized learning path by the sequence of learning knowledge. Students who were majoring in mathematics were invited to participate in the experiment. Experimental result demonstrates that LD-LP works effectively and it has high adaptivity and positive feedback.