Main melody films are propaganda works that pay tribute to the Chinese nation, the party and the army. Since the turn of the century, they have gradually developed into the main genre of Chinese cinema, and its "blockbusterization" is arguably the most phenomenal aspect of the 2010s Chinese film industry. As an increasing number of Hong Kong directors are commissioned to direct main melody blockbusters, Chu examines their contributions to this genre, shedding light on the development of cross-border cooperation between the mainland and Hong Kong film industries.