'China is willing to jointly develop areas of the South China Sea with Vietnam,' state television quoted Hu as telling Trong.
The countries should 'not allow the maritime issue to affect relations between the two nations and two parties', said Hu, who also heads the Chinese Communist Party.
Meetings between leaders of communist neighbours China and Vietnam are normally presented as party-to-party rather than state-to-state.
Hu was quoted as saying the two nations should maintain dialogue and prevent their differences from becoming 'more complicated'.
Trong arrived in China earlier Tuesday for a five-day visit timed to coincide with the 20th anniversary of the normalization of diplomatic ties after a brief naval battle over the disputed Spratly Islands in 1988.
It is Trong's first trip to China since he became General Secretary of the Vietnamese Communist Party in January, Chinese state media said.
China said talks with Vietnam in late June over maritime areas near the Spratlys had eased tension that had built earlier this year.
The Chinese Foreign Ministry said the two sides promised to 'prevent words and actions that would be detrimental' and agreed to accelerate negotiations on basic principles for resolving maritime disputes.
But Hanoi issued a formal protest in August after Chinese ships carried out a scientific survey near the islands.
China claims the entire Spratlys, which are believed to be rich in oil, mineral and marine resources. The islands are also claimed in whole or in part by the Philippines, Brunei, Malaysia and Taiwan.
China and Vietnam fought a brief but violent border war in 1979, but economic and diplomatic ties have gradually improved over the last decade.
