With the evolution and development of diversified businesses in the Internet of Things, the NB-IoT network is hard to support the 5G IoTs. In order to speed up the recovery of industrial weaknesses, the Ministry of Industry and Information Technology pointed out in the "5G Application action Plan (2021-2023) "[1] that according to the characteristics of different versions of 5G international standards, 3GPP R17 version focuses on medium and highspeed, large-connection applications, and carries out technology, industrialization and application introduction in stages. As a "lightweight" 5G technology, RedCap with multiple characteristics such as low-cost terminal, low-power consumption, easy network evolution, and support for medium and high-speed business needs, it comes into being at the right time to promote the scale application of 5G terminals, expand the ecosystem of 5G equipment, and expand 5G application scenarios.This article focuses on the global Internet of Things evolution and market development, RedCap outlook, basic theory, practical use cases, and subsequent market outlook and other dimensions, a comprehensive and in-depth analysis of RedCap follow-up research direction, to support better market development in the future.