Non-specific chronic low back pain is the most common self-reported kind of musculoskeletal ache associated with substantial health and socioeconomic problem and responsible for most years lived with a disability as compared with any other medical condition. So treating chronic non-specific low back pain is one of the main problems faced among physical therapists in the rehabilitation area. The effects of ultrasound for patients with non-specific chronic low back pain remain unknown, however it is commonly used to treat clients with low back pain in rehabilitation setting. Therefore, the main aim of this review was to evaluate the up-to-date confirmation in the efficacy of ultrasound therapy on the treatment of non-specific chronic low back pain. A comprehensive search of four computerized electronic databases was performed to identify the effectiveness of ultrasound therapy on the management of chronic non-specific low back pain. Searching was done through the Google Scholar, PubMed, ScienceDirect, and Physiotherapy Evidence Databases (PEDro) and reported using preferred reporting items for systematic reviews and meta-analyses guidelines. The qualities of articles were appraised by the PEDro scale. The primary outcome measure visual analog scale was used. Six randomized clinical trials with a total sample size of 699 patients from the electronic database published in English were identified. In this review, the effect of UST in five articles was statically significant in reducing the visual analog scale (p<0.05) score. So this systematic review found ultrasound therapy could be an alternative treatment to reduce the intensity of pain in subjects with non-specific chronic LBP.