Abstract: The dangerous rockmass studied in this paper is located at the foundation site under a small ancient pavilion,under the premise of protecting ancient buildings,the difficulty of controlling dangerous rockmass increases obviously.Because of the high and steep location of the dangerous rockmass, and a inverted pyramidal collapse cave chamber has been formed below it,moreover, there is a landscape path of the characteristic landscape park of Shijingshan ancient construction mountain body located at the foot of the steep slope of the dangerous rockmass, severe challenges to the treatment of dangerous rockmass are posed. After comparing and selecting several schemes, the measure of I-steel inclined bracing inner support ring under the dangerous rockmass is taken. As the observation during the construction and upon completion, it has a good effect on the protection and treatment of small ancient pavilion foundation. This study can be used as a reference for dangerous rock treatment projects under similar special conditions.