Background: Nonspecific neck pain (NNP) is a common type of neck pain that causes serious health problems and is closely related to myofascial pain syndrome (MPS). Here, we compare the effectiveness of ultrasound-guided trigger point injection therapy (TPI) and conventional physical therapy treatment in patients with NNP in multiple dimensions. Methods: Thirty-eight patients with NNP were randomly assigned to the control group and ultrasound-guided TPI group, a single dose of 3 ml of 0.5% lidocaine was injected into each trigger points in all affected muscles under ultrasound guidance once a week for three weeks. The controls received conventional physical therapy treatment every other day for a total of three weeks. The visual analog scale (VAS) score, neck disability index (NDI), surface electromyography (sEMG), sonoelastography and infrared thermography characteristics were used to measured the effectiveness one week and four weeks after the whole treatment. Results: Compared with the control group, the TPI group showed improved pain and functional disability both at one-week and four-week assessment(P<0.01); and the TPI group showed improved electrical activity (P<0.05), elastic stiffness and skin temperature at the four-week assessment(P<0.01). Conclusions: Ultrasound-guided TPI on upper trapezius muscle can alleviate the pain, improves dysfunction for NNP than conventional physical therapy, and the multiple evaluation methods in treatment is more conducive to explore the underlying mechanism of NNP.Trial registration: The present study has been retrospectively registered on Chinese Clinical Trial Registry website (ChiCTR2100051009), Registered 10 September 2021.