Ultrasound guided quadratus lumborum block (QLB) is a new emerging trunk block which can be used as an adjunct analgesic measure in many lower extremity, abdominal and lumbar surgery. As an important constituent part of multimodal analgesia, ultrasound guided QLB is an easily performed technique with definitely analgesic effect, which has bright prospects in clinical application. However, the understanding of QLB of anesthesiologist in our country is not sufficient and still needs to be improved. This review focuses on the anatomy of quadratus lumborum and thoracolumbar fascia, the possible mechanism, dose of local anesthetics, 5 different approaches and associated dermatome block area, clinical application as well as the complications of ultrasound guided QLB technique.