In the wake of China's "Double Reduction" policy, the prohibition of after-school tutoring centers has led to a rise in parental assistance in their children's homework, concurrently elevating parental anxiety as homework assistant. This research aims to explore the effect of parental self-efficacy on the parental anxiety as homework assistant of elementary students in the context of China's "Double Reduction" policy, particularly focusing on the mediating role of effective homework management by parents. Through a questionnaire survey involving 1032 parents of first through sixth graders in China, this study discovered a significant effect of parental self-efficacy on parental anxiety as homework assistant. It was observed that environment--time and motivation--emotion management mediated the relationship between their self-efficacy and parental anxiety as homework assistant. Notably, a high degree of parental self-efficacy tends to exacerbate educational anxiety by enhancing their focus on environment--time management, while simultaneously, it can mitigate this anxiety by cultivating better motivation--emotion management. These findings shed light on novel strategies to alleviate parental anxiety, offering significant insights for the effective homework management of children' homework.