The purpose of this study was to examine the effects of ability beliefs, academic contingencies self-worth (ACSW), and academic achievement on elementary school students’ learning motivation and affects. A three-factor quasi-experimental design (2 × 2 × 2) was adopted. Participants were 121 sixth-grade students of four intact classes from two elementary schools in Taipei and Kaohsiung. Students of two classes were primed with the incremental ability belief when learning science article, and the others primed with entity ability belief. Furthermore, the students were divided into high and low ACSW groups by their scores on ACSW Scale and high and low achievement groups by their scores on The Science Article Achievement Test. Data were analyzed using a  three-way ANCOVA. The independent variables were ability beliefs, ACSW, and achievement. The covariates and dependent variables were pretest and posttest scores, respectively, of Elementary School Science Knowledge Learning Motivation Scale and Elementary School Science Knowledge Learning Affect Scale. Results  Suggested that students with high achievement showed higher learning motivation on value, expectation, and affect components than low achievement students only when they had high ACSW and were primed with entity ability belief. There were no differences under other circumstances. Also, students who were primed with incremental ability belief experienced higher nervous affect than students primed with entity ability belief. Finally, based on the research findings, implications for educators and suggestions for future research were provided.