According to the three-step analgesic principle, oral administration is the most common method of drug delivery. There are also various methods such as intravenous, rectal and transdermal administration. Some special treatments such as nerve blocks can also be applied in analgesic treatment. Analgesia should be started with the simplest dosing regimen and non-invasive treatment means, and the treatment effect should be closely observed. Transdermal administration or mucosal administration can be considered for patients who are unable to take drugs orally or have absorption disorders. In addition, subcutaneous, intramuscular or intravenous administration may be considered for patients with eruptive or refractory pain. The third step of drug administration should be based on the principles of timely administration and individualized dose, and the traditional concept of morphine administration (fear of addiction, emphasis on respiratory depression) should be removed, and the drug should be administered mainly according to the patient’s tolerance level, with the goal of complete pain relief. The “on-time administration” can maintain a stable blood concentration, which can effectively relieve pain and avoid euphoria, and is not easy to become addicted. ”Giving drugs when it hurts” is a big taboo in cancer pain treatment, except when morphine is titrated. The clinical dosage of morphine is highly variable and is related to individual differences in sensitivity to opioid receptors, therefore, clinical use should follow the principle of individualized dosage. Morphine preparations should be used rationally to completely relieve patients’ pain with proper assessment of their pain level. In addition to the three-step ladder, some scholars have proposed the fourth step, namely interventional analgesic treatment. It mainly includes invasive operations such as neurodesis or ablation, but its safety and practicality have been confirmed by several studies.