Background： Patients with intractable cancer pain compose about 3%-20% of those with cancer pain, and the intractable pain degrades patients’ life quality severely. The inordinately stress caused by the acute pain will also degrade immune function severely. Morphine associating with ketamine to cure patients’ intractable cancer pain can academically relieve immune suppression, which is still short of experimental data to support internationally now. Objective：This overview initially investigates the cell immunomodulation and its mechanism of morphine associating with ketamine to cure patients’ intractable cancer pain. Content：Morphine is the most important and most widely-used clinical drug for advanced cancer pain, but long-term and generously applicating morphine will lead to tolerance and hyperalgia, and morphine itself restrains organism immunization. Low-dose ketamine can antagonize thoseeffects of morphine and therefore decrease morphine dosage. Combination of these two drugs will generate synergism and addition effects of relieving immune suppression by relieving pain and excessive stress. At the same time, these two drugs can immediately act on the corresponding receptors of immunocytes and produce changes of function and quality. The mechanisms maybe intimately refer to NF-κB、NO、cAMP and cGMP. Trend：This paper will provide theoretical support for the study of the immunological effects of morphine associating with ketamine for the intractable cancer pain.