Informed consent and patient autonomy rights require an optimal cancer diagnosis disclosure strategy to be used to update the patients and caregivers with the bad news. However, a cancer diagnosis disclosure may arouse anxiety and distress which increase patients’ and caregivers’ psychological burden. This study aims to explore the influence of cancer diagnosis disclosure on the quality of life in elderly cancer patients and their caregivers, and to introduce an effective way to disclose cancer diagnosis. A total of 120 participants were randomly selected in the study. The Medical Coping Modes Questionnaire was used to select informed person. The SPIKES was used to guide the disclosure procedures. The informed patients’ or caregivers’ quality of life were evaluated by the Generic Quality of Life Inventory-74 or Caregiver Quality of Life Scale before and after the cancer diagnosis disclosure and at the discharge time. After cancer diagnosis disclosure, no significant change was found on the quality of life of the informed person. With multiple psychological interventions implemented, a significant increase was noticed on the quality of life of the informed person. Applying the cancer diagnosis disclosure strategies and psychological intervention were essential to improve cancer patients’ and caregivers’ quality of life.