This study is aimed at formulating competitiveness index system for Chinese medium-sized construction enterprises entering overseas international construction markets and evaluate a company's competitiveness by adopting grey theory. An analytic network process (ANP) method is adopted to establish a set of competitiveness index system for medium-sized construction enterprises. Subsequently, grey correlation analysis is used to evaluate competitiveness relative to that of other enterprises based on limited available information. Through expert evaluation and ANP, the weights of the index system are calculated, and indicators with the highest weights are identified. The top five indicators are industry structure, industrial organization status, brand resources, enterprise system, and enterprise size. A case study is conducted, and the following conclusions are drawn that using grey correlation analysis and the competitiveness system, enterprises can judge their competitiveness level against that of rivals in the international market. This study can help Chinese medium-sized construction enterprises evaluate their international market competitiveness through expert evaluation methods, the ANP, and grey correlation analysis in a comprehensive and innovative manner.