This quasi-experimental study examined the effects of digital game-based learning (DGBL) on elementary-school students' Chinese language learning, self-efficacy and attention. In total, 126 fourth-graders participated in the study for 6 weeks. Two digital games with different mechanisms (completion-contingent and performance-contingent rewards) that integrated content from the fourth-grade Chinese language-arts curriculum were developed. Data on attention were collected from wearable electroencephalographic sensors while participants played the games. Students' playing behaviours were coded into five patterns. Students in the DGBL groups outperformed those in the control group in Chinese language-arts learning. Different game mechanisms had significant positive effects on children's attention and self-efficacy. The performance-contingent reward game significantly enhanced students' attention, and the completion-contingent reward game significantly enhanced their emotions and confidence in the Chinese language arts. The performance of more leaning behaviours in the DGBL environment was associated with higher Chinese language-arts achievement scores, especially among players with high levels of attention and self-efficacy during game play. These findings support the effectiveness of DGBL in enhancing students' Chinese language learning.