Chronic noncancer pain (CNCP) is common in clinical practice and has many etiologies. The patients with CNCP are usually associated with physical, emotional and social disability, and often complicates its management. The mode of total care in palliative medicine should be an important modality in managing patients with CNCP. Opioids are the drug of choice for the moderate to severe cancer pain relief. There are still some debates in the long-term opioid therapy of patients with CNCP, mainly because of the consideration of its efficacy, adverse effects, and the risk of addiction.. In this article, we will discuss the basic knowledge of CNCP, the evidence-based efficacy of opioid therapy, and legal regulation from the government.