This research adapted interpersonal attribution theory to investigate whether children’s perceived parents’ attribution style impacted on math achievement motivation. The research design was quasiexperimental with pre- and post- test. The participants were 109 Grade 5-6 students divided randomly into 5 experimental groups. A scenario simulation method was adopted, using five films about parents’ verbal feedback (lack of ability, effort and strategy) and emotion responses (anger and compassion). After treatment, a one-on-one structured interview about children’s personal and interpersonal perception of attribution style was used to collect status data. The data was analyzed using a chi-square test. The results showed that Taiwanese children’s attribution bias was mostly linked to lack of effort, and associated with personal belief and their perceptions of parents’ reactions. The conclusions were that moral meaning of effort was deeply embedded in children’s beliefs, and that interpersonal attribution was still impacted by children’s subjective perceptions. Interpersonal attribution theory was partly verified. Taiwanese children attributed parents’ anger to lack of effort, and perceived incorrectly parents’ sympathy to anger but not to lack of ability.