Abstract: With the development of ultrasound-guided regional anesthesia techniques, the peripheral nerve block technology has been widely used in clinical practice. As an emerging local anesthetic adjuvant, methylene blue can prolong the nerve block time and enhance the analgesic effect, so it is widely used in peripheral nerve block. However, there are still disputes in the characteristics of action, route of administration, efficacy and safety of methylene blue. This paper reviewed the pharmacological properties of methylene blue mechanism of action, and its effectiveness and safety in peripheral nerve block, with the aim of providing reference for clinical practice.