Castro and his delegation, including Foreign Minister Bruno Rodriguez Parrilla, flew out of Havana Sunday.
Castro’s visit to China from July 4-7 will be his first to that country since he took office in 2008.
Cuba and China established diplomatic relations in 1960.
China is Cuba’s second largest trading partner with their trade volume reaching about $1 billion in 2010, according to Xinhua.
Havana established diplomatic ties with Vietnam in the same year as China. Both countries have supported each other on international affairs.
Trade between Cuba and Vietnam reached $269 million in 2010.