Hypertrophic scar may often occur after burns or surgery and this greatly affects the body appearance and body functions. Conventional scar assessment is very subjective with only eye watching and finger feeling. Thus, it is difficult to provide accurate outcome measurement for various treatments. Ultrasound imaging is effective for scar evaluation, but conventional ultrasound devices are normally too bulky and expensive, and also need someone with professional knowledge to operate. Therefore, we have developed a novel smartphone-based wireless ultrasound device for the evaluation of scar and other tissues. The smartphone is used to control ultrasound measurement and imaging, processing and display ultrasound signal and images.