Narcotic plants are strictly regulated worldwide due to their ability to extract drug alkaloids and drug precursor components. Besides the three traditional core species, cannabis, opium poppy, and coca, the misuse of psychoactive plants with addictive properties has become increasingly prevalent globally in recent years, and the establishment of accurate identification methods for such plants has become an urgent need in the field of narcotics control. Within existing identification frameworks, the conventional morphological and chemical analysis methods, despite their long-term application, have demonstrated considerable limitations. In contrast, DNA-based molecular identification techniques have achieved significant advancement in recent years due to their high specificity and stability. This review comprehensively examines current DNA-based identification approaches for narcotic plants through three key dimensions: DNA molecular marker technology, DNA barcoding technology, and emerging molecular biological techniques, and elaborates on the principles, technical characteristics, application scenarios, and research progress of each technology, providing some reference for the scientific selection of DNA identification strategies for narcotic plants in different specific scenarios.