Classroom dialogue is widely used in mathematics teaching and learning, and if managed strategically, it will have productive benefits for mathematics achievement. However, dialogic participants often lack awareness of how dialogue could be constructed, and few studies show the characteristics of dialogic patterns in different stages of education. Drawing on the data from the Chinese National Cloud Platform, this study therefore comparatively examined the dialogic patterns of mathematics lessons captured in primary, secondary and high schools in China, using 300 video-recorded mathematics lessons, with 100 lessons for each stage of education. Classroom dialogue was transcribed and systematically coded, after which a lag sequential pattern mining technique was used to examine the collective process of dialogic contributions. Findings indicated that there were both similarities and differences in terms of the dialogue pattern throughout the three stages. Dialogue concerning previously-learnt knowledge, subjective expressions and analysis appeared frequently in mathematics lessons in the three education stages, while speculative talk and querying were less often observed. There were commonalities between dialogic patterns captured in mathematics lessons in secondary and high schools, which were significantly different from those in primary schools. The variation was most obvious in dialogue showing high-level cognition, namely, analysis, coordination and speculation. Prominent sequences captured in secondary and high school lessons were able to involve dialogue at both low and high cognitive levels, which demonstrated the characteristics of exploratory talk. This knowledge could help create productive classroom dialogue, and benefit mathematics teaching and learning.