Objective To construct blended teaching mode (online and offline teaching and learning) for the course of Obstetrics and Gynecology Nursing and to test the teaching effect. Methods Based on framework for interaction and cognitive engagement in connectivist learning, we developed blended teaching mode: formulating theoretical framework for teaching mode and designing teaching forms, methods, process and effect appraisal. Then the teaching was provided for 223 undergraduate nursing students of Grade 2015 and 2016 in the course of Obstetrics and Gynecology Nursing. Results The scores of theoretical tests were (75.97±9.03) in students of Grade 2015 and (78.45±10.86) in students of Grade 2016 respectively. More than eighty percent (85.1%) of the students believed that the teaching mode could be applied to other courses of nursing subject, 94.9% of them thought that the teaching mode promoted their cognitive engagement, and 75.3% of them reported the form and contents of online teaching resources should be further improved. Conclusion The blended teaching mode from the perspective of cognitive engagement can improve teaching effect of the course of Obstetrics and Gynecology Nursing.