This paper estimates Guangdong and Shandong's marketization indexes and industrial cluster degrees to analyze their impacts on economic growth based on Samuelson model which induces maketization variable and clusterization variable. The analysis shows that clusterization advantage is the main reason why Guangdong's economic growth has been higher than Shandong's since entering 21th century compared with marketization factor, clusterization's economic growth contribution rate is much higher than marketization's, and clusterization has unlimited room to expand. Today, differences of marketization among regions are increasingly smaller, local governments should speed up the introduction of cluster policies to guide the direction of industrial development from agglomeration to cluster, to promote sustainable economic growth.