An understanding of the equal sign is a fundamental concept for early algebra. While literature claimed that Chinese students commonly master the relational understanding of the equal sign in the elementary school, these claims are under-researched. This study used the Mathematics Equivalence Assessment with 237 Chinese Grade 5 students. The results showed that the majority of students possess a relational understanding of the equal sign, with some able to confidently apply the concept of structural equivalence. To complement the test results, six Grade 5 teachers were also interviewed to explore teaching approaches and contexts used to foster an understanding of the equal sign.