Abstract: Loess is a special kind of soil with very unique characteristics in China. Its vertical joints are developed. When it meets water it is easy to soften, while its physical and mechanical properties could decline sharply, and so it has remarkable engineering characteristics. The depth of a loess tunnel is generally shallow with obvious scale effect.During construction, it is prone to various issues such as collapse, surface cracking, lining cracking, substrate settlement, loess slope deformation, and loess sinking, etc. In recent years, relying on the construction of the loess tunnels of high-speed railways such as the Zhengzhou-Xi′ an high-speed railway, the Datong-Xi′ an high-speed railway and the Baoji-Xi′an high-speed railway, as well as the loess tunnels of metro projects in Xi′an, Zhengzhou, Luoyang and Lanzhou, a series of scientific researches have been carried out, which have obtained rich research results, providing good guidance to the engineering practice. With the continuous progress of construction technology and equipment level as well as the implementation of various tunnel projects in loess areas, this paper summarizes the state of the art in terms of the basic theory, survey and design, construction, operation and maintenance of loess tun? nels. With consideration to the actual problems arising in the current engineering construction, it puts forward some new technologies, new trends and new ideas pending for further research and breakthrough, which could provide a reference for the continuous development of loess tunnel construction technology in the future.