Objective To investigate the clinical effect of child-friendly nursing based on Goal Attainment Theory during the perioperative period in children undergoing day surgery. Methods Using convenience sampling, pediatric patients undergoing day surgery at the Day Surgery Center of West China Hospital, Sichuan University, between July 2024 and January 2025 were selected as the study participants. The patients were randomly assigned to an intervention group or a control group using a random number table. The control group received routine perioperative nursing care, while the intervention group received child-friendly nursing based on Goal Attainment Theory in addition to routine care. Anxiety [modified Yale Preoperative Anxiety Scale (m-YPAS)], crying behavior, treatment cooperation, and family members’ satisfaction with nursing care were compared between the two groups before and after the intervention. Results A total of 120 pediatric patients were included, with 60 patients in each group. After the intervention, the intervention group had lower m-YPAS scores [(33.46±4.37) vs. (45.25±5.63) points], fewer crying episodes [(1.49±0.42) vs. (3.48±0.45) episodes], and shorter duration of each crying episode [(4.23±1.84) vs. (7.37±2.36) min] than the control group (P<0.001). The overall treatment cooperation rate was higher in the intervention group than that in the control group (91.67% vs. 78.33%; χ2=4.183, P=0.041). The overall satisfaction rate of family members with nursing care was also higher in the intervention group than that in the control group (95.00% vs. 81.67%; χ2=5.175, P=0.023). Conclusion Child-friendly nursing based on Goal Attainment Theory can alleviate perioperative anxiety and crying behavior in pediatric patients undergoing day surgery, improve treatment cooperation and family members’ satisfaction with nursing care, and has potential clinical application value.