This study examined effects of gamified comparison on sixth graders' performance of algebra word problem solving and attitude toward algebra learning. Seventy-two sixth graders were invited to participate in a four-week experimental instruction and assigned to three groups: gamified comparison, comparison, and control. The results showed (1) a significant effect on solving similar problems: the gamified comparison group performed significantly better than the comparison group and the control group respectively, and the comparison group performed significantly better than the control group; (2) a significant effect on solving transfer problems: the gamified comparison group gained significantly higher scores than the comparison group and the control group respectively, and the comparison group gained significantly higher scores than the control group; (3) a significant effect on students' learning attitude: while no significant differences found on students' confidence, the gamified comparison group made significantly more positive responses than the comparison group and the control group in terms of enjoyment, motivation, and perceived value. This study proposed a feasible combination of game rule and comparison strategy, as well as exploring implications for teachers' teaching design and students' gamified learning activities.