In Chinese culture, academic achievement is seen as an important measure of the success of family education and crucial to the future development of adolescents. This study aims to examine the relationship between parental encouragement and academic achievement and their mechanisms for students in China. A questionnaire was used to survey 2,894 eighth grade students. The results show that: (1) Parental encouragement improves students' academic achievement; (2) Optimism plays a mediating role between parental encouragement and students' academic achievement; (3) Perceived stress plays a mediating role between parental encouragement and students' academic achievement; (4) Optimism and perceived stress play a chain mediation role between parental encouragement and students' academic achievement. This study explores the impact of parental encouragement on students' academic development and personality development, and has real significance for guiding family education.