Breath and heartbeat are important vital signs, which can indicate the existence of living body and related states. Accurately acquiring life information in collapsed space and building interior plays a huge role in emergency rescue and counter-terrorism. Ultra-wide band radar has strong penetration and anti-interference performance, and can penetrate walls to detect human vital signs, which has become a research hotspot in the field of life detection. This paper summarizes the current development status of ultra-wide band radar life detection equipment at home and abroad, including the main research teams and their typical product characteristics. The overall framework of through-wall vital sign signal detection technology based on ultra-wide band radar is sorted out, and the four parts of echo signal denoising, echo signal enhancement, echo selection and distance positioning, and vital signal separation and reconstruction are introduced in detail, and the application status of deep learning in vital sign signal detection is analyzed. Finally, from the perspective of products and technology, future research directions are prospected.