Abstract-The rapid development of UHVDC power transmission makes the proportion of external power accepted by provinces increase significantly. This paper aims at analyzing the relevancy of UHVDC power transmission and provincial power source construction from two aspects of reliability and environmental protection, as well as finding the relevancy characteristics. Firstly, we establish the evaluation index system for power source construction and UHVDC power transmission. Secondly, we establish the correlation model based on the grey correlation analysis algorithm, and solve models by using Matlab software programming. Last, we take a province and an ± 800kV UHVDC power transmission engineering for example to conduct a case study. According to evaluation index system and data mining, the research calculates grey correlation value of the UHVDC power transmission and power source construction system, and qualitatively and quantitatively analyses the relevancy characteristics between the above two systems. The result reveals the inner relevancy and dominant factors between the ± 800kV UHVDC power transmission and provincial power source construction.