Students expose various intuitions in probability comparison and calculation tasks. Large volumes of research looked into these intuitions by categorizing learners' strategies, but fewer studies considered how these intuitions may be associated with learners' judgments. Even fewer examined the mixed effects of multiple intuitions held by the same individual. Despite calls from scholars to explore students' understanding of probability in different cultural contexts, there has been a dearth of research on how Chinese students understand probability. This study explores the relationship between students' multiple probability-related intuitions and their judgments in the probability contexts among middle school students in China. In this study, we sampled 707 7th-9th graders from Qingdao, China. We measured students' performance in probability comparisons and calculations and their probability-related intuitions about equiprobability bias and representativeness heuristics. With chi-square tests and multinomial logistic regression analysis, the relationship between the 2 intuitions and students' judgments in probability comparison and calculation tasks was examined in detail (including dual effects). The findings of this study include, first, that at the middle school level, students' equiprobability bias and representativeness heuristics fade with age, but they do not disappear completely. Second, students' intuitions may play a role in solving probability problems, where equiprobability bias may induce them to make an "equal probability" judgment and representativeness heuristics may make them consider a mixed outcome more likely to occur. Third, the 2 intuitions coexisted and influenced students' responses together, but the sensitivity of these dual effects to the students' judgments in the qualitative comparison and quantitative calculation tasks differed. This study will contribute to the fast-iterating policymaking in probability education in China by advocating that curriculum standards pay more attention to students' limitations in conceptual understanding and their exposed intuitions or misconceptions. This study may, to some extent, complement previous works focusing on Western students' probability intuitions by confirming that, even for Chinese students who performed well in PISA, their probability perceptions are also accompanied by intuitions.