The World Health Organization’s three-step principles for cancer pain treatment include: 1. oral administration: oral administration is the preferred route of drug delivery, and patients who cannot take drugs orally can choose other routes of drug delivery; 2. timely administration: drug action has a duration, and failure to administer drugs on time will easily lead to recurrent pain and affect the long-term treatment effect; 3. by step: drugs of different steps are chosen according to the degree of pain; 4. attention to specific details: pay attention to close observation of patients to avoid or reduce the occurrence of side effects; 5. individualized drug delivery: each person has different pain tolerance and drug sensitivity, and different doses of drugs are administered.