The invention relates to an optimal selection method of an extra-high voltage transformer substation location. The method is characterized by: firstly, establishing an index parameter which is used to plan an extra-high voltage transformer substation location layout; carrying out a system comprehension assessment on the location of the extra-high voltage transformer substation from five aspects of an economic index parameter, a security index parameter, a location area characteristic index parameter, a perspective adaptability index parameter and a coordination index parameter; according to the assessment, providing an extra-high voltage location grey integration optimization selection method based on a moment estimation theory; through the moment estimation theory, considering a subjectivity of a decision maker and objectivity than weight changes as time flies; finally, through the grey integration optimization selection method, carrying out optimization selection of a decision scheme. The method of the invention provides an important theory guidance for the extra-high voltage location program and possesses scientificity and rationality.