Objective To construct an online platform to support fertility information for young breast cancer patients and to evaluate its application effect. Methods Relying on Internet technology, a patient needs-oriented online platform was developed to meet the fertility information needs of young breast cancer patients during the whole course of treatment. A total of 52 young breast cancer patients who had not yet started treatment were divided into a control group (n=27) and an intervention group (n=25) according to their admission time.The control group was given routine health education, and the intervention group received alternative education through the online platform.The effect was evaluated after 3 months of intervention. Results Twenty-five patients in the control group and 24 in the observation group completed the study.Compared with the control group, the intervention group had significantly lower Reproductive Concerns After Cancer （RCAC） scale score, while higher fertility knowledge and Medical Outcomes Study Social Support Survey （MOS-SSS） score after the intervention (all P＜0.05).More than eighty percent (83.33%-100%) of the patients in the observation group had positive attitudes toward the use of the platform. Conclusion Application of the online platform to support fertility information can reduce fertility-related concerns of young breast cancer patients and improve their fertility-related knowledge and medical social support, which is well received by patients.