As the main way to protect important cultural relics such as grotto statues and murals,eave architecture has existed for a long time in the process of historical development and has been accompanied by grotto temples.However, most eave architecture cannot withstand the erosion of the years and were destroyed. People have gradually adapted to the style of the grotto temple without eave architecture. Therefore, the restoration of eave architecture based on the basic principle of protecting the "authenticity" of cultural relics has caused a long-term controversy. The main problem is that the form of eave architecture is easy to be overwhelmed by the audience, which leads to changes in the appearance of the grottoes.This article systematically sorts out the form, function and development process of eave architecture, clarifies the root cause and connotation of eave architecture, and emphasizes the historical status of eave architecture as the composition of grotto temples and the value of the unique "semi-architectural" construction method.Furthermore, it is proposed to take the protection of the cultural relics as the foundation and the principle of responding to the needs of the times, and explore the diverse ways and methods of creating the front space of the eave architecture in the current era, in order to further the overall sustainable protection concept of the grotto temple cultural relic promote.