Situated in a special sociocultural context, teacher collaboration moves away from its original purpose under the tension between external constraint and professional autonomy. The Chinese mainland promotes "open class" match to develop collaborative school culture and to enhance teacher professionalism. However, it reveals that teacher collaboration encounters difficulties when it is under the tension between external constraint and professional autonomy. Activity agenda and rules are under the control of administrators and academic authorities. Teachers are forced to follow external disciplines, and their professionalism is suppressed. In order to improve teacher collaboration, it needs to get rid of instrumental rationality, get out of "model play," and empower teachers.