The invention discloses a device for diagnosing diseases of a skeletal muscle system based on multi-physics field coupling and a method thereof, and belongs to the technical field of diagnosis of related diseases of the skeletal muscle system. The device is composed of a soft tissue mechanical modulus field and flow field measuring device, a soft tissue surface temperature measuring device, a man-machine interaction system and an examining table. According to the invention, soft tissues such as muscles, tendons, ligaments and blood vessels around the skeletal muscle system disease are used as test objects for the first time, and the lesion mechanism of the skeletal muscle system disease is explored; by means of the device, in-vivo, non-invasive, real-time and quantitative detection of multi-physics field parameters such as a mechanical modulus field, a flow field and a surface temperature field of soft tissues such as muscles, ligaments, tendons and blood vessel walls can be achieved, and through multi-physics field contrastive analysis and neural network deep learning, data support and theoretical basis are provided for quantitatively revealing a new lesion mechanism of the skeletal muscle system diseases, and meanwhile, an in-vivo noninvasive device and method are provided for early diagnosis of the clinical skeletal muscle system diseases.