Objective To develop a digital ICU diary nursing program for patients undergoing mechanical ventilation in the intensive care unit (ICU) and to create an accompanying digital ICU diary application，to provide references for implementing the concept of humanistic care in ICU nursing and facilitating patients′ psychological recovery. Methods A preliminary draft of the electronic ICU diary nursing program for critically ill patients undergoing mechanical ventilation was formed through a systematic literature review and qualitative interviews. Based on the Delphi method, two rounds of questionnaire consultations were conducted to form the final version. Based on this program, an electronic application for the electronic ICU diary nursing program for critically ill patients undergoing mechanical ventilation, named "Doctor-Patient Heartfelt Communication" was designed. A pre-test involving five groups of patients and their families was conducted in September 2024 to validate the operability and feasibility of the program. Results The effective return rate of the expertconsultation was 100%.The authority coefficients of the experts were 0.891 and 0.922, respectively, while the overall coefficient of variation was 0 to 0.409 and 0 to 0.235. The Kendall′s concordance coefficient were 0.204 and 0.211 (both P<0.05). The final digital ICU diary nursing program for mechanically ventilated patients consisted of five primary items, 17 secondary items, and 61 tertiary items. All participating patients and families completed the digital diary recording process, with an average time of less than 8 minutes per record, confirming the operability and feasibility of the program and application. Conclusion The electronic ICU diary nursing program for critically ill patients undergoing mechanical ventilation is scientific, reliable, comprehensive and specific in content, and highly feasible in clinical practice. It can provide a reference for ICUs to implement humanistic care measures for critically ill patients undergoing mechanical ventilation to promote their psychological recovery.