Taking an exploration horizontal hole construction as the example, which was in the oversize dangerous rocks zone in Huangyanwo and Banbiyan of Yangtze River Wuxia, the construction scheme of drilling platform was explored, the construction was carried out under the conditions of approximate vertical rock beetling wall without ground foundation. With the stress system of diagonal braces and anchorage structures, a complete set of construction technology is developed by the mechanical analysis and calculation, which has certain guidance and reference value for solving difficulties of similar engineering construction platform.