Rotary drilling rig is a kind of construction machinery which is widely used in hole forming operation in building foundation engineering, especially suitable for drilling construction of various stratum structures. In this paper, the construction technology of rotary drilling rig foundation and the dynamic control method of its key parameters in overhead transmission line engineering are studied in detail. Based on the analysis of construction technology, an intelligent control method of construction parameters for key steps is proposed, including the analysis model of rig stability, drilling accuracy and steel cage structure stability. Through the calculation of actual construction data, the applicability and scientificity of the proposed method and model are verified. These innovative methods and models provide scientific decision support for the foundation construction of overhead transmission line projects, and help to promote the progress of construction technology and the modernization of construction management.