Integrated science is a ubiquitous school subject that is found in primary and middle-school levels around the world. Being a hybrid subject comprising several science disciplines, it poses many challenges to teachers as they are obliged to teach beyond their disciplinary comfort zones. In addition, this subject is prone to a lack of coherence, which helps people see how a small number of key ideas in a discipline can build upon each other to deepen understanding. Using integrated science textbooks from mainland China since 1990 as a case study, their (i) disciplinary emphasis (i.e. which topics & disciplines were emphasised) and, (ii) coherence of topics were therefore examined. The results showed that physical science topics were heavily and consistently emphasised in these textbooks, which likewise corresponded with the high number of buttress topics found in this discipline. Life science topics were the next most emphasised followed by earth science ones, a trend present since the 1990s in this country. We conclude with implications for improving science teacher training/professional development as well as student scientific literacy from this study of disciplinary emphasis and coherence in integrated science textbooks.