Scientists’ participation in science communication is essential to the communication between the public and the scientific community. Therefore, how to improve scientists’ enthusiasm and continued participation in this regard is a practical question. Through in-depth interviews with 27 scientists, media practitioners, university officers and relevant researchers in China based on grounded theory, this study explores the motivations and perceived conditions affecting scientists’ initial and sustained participation, analyses the possible relationships between the predictors and the motivation–attitude–behaviour mechanism of scientists’ participation and puts forward corresponding suggestions to provide references for related research and practice.