Objective To explore the effect of an intelligent nursing decision support system applied in breast cancer patients under-going chemotherapy.Methods One hundred patients receiving chemotherapy for breast cancer were divided into a control group and an intervention group chronologically, with 50 in each group.The control group was given nursing care based on the hospital information system, while the intervention group received intelligent nursing care using a self-designed intelligent nursing decision support system.Results The rate of correct nursing diagnosis and the rate of consistency between nursing records and nursing shift were significantly higher, whereas the time consumed in nursing documentation was significantly shorter in the intervention group compared with the control group (all P＜0.05).Greater than eighty percent (86.67%-100%) of nurses were satisfied with the intelligent nursing decision support system.Conclusion The intelligent nursing decision support system can improve the precision and efficiency of nursing care and gains recognition from nurses.