Under the background of a "Internet Plus" tide, according to the characteristics of the mathematic teaching theory and students' mathematic level, a blended teaching mode is adopted which consists of online autonomous learning module before class, flipped teaching module in classroom and extended learning module after class. The design concept is elaborated and the design details in modules are presented. Through comparative experiments, it is found that compared with the conventional offline teaching mode, the blended teaching mode can enhance participation, advance deep learning ability and improve the learning effectiveness and promote the cultivation of application ability. It is suggested that the mixed teaching mode be applied to normal students of mathematics based on their characteristics.