Mr Yang said it was important to build up Africa's infrastructure
China says it will give a $7m (£4.4m) grant to help fund infrastructure development projects in Kenya.
The announcement came at the start of the Chinese Foreign Minister Yang Jiechi's latest Africa tour.
His schedule includes visits to Nigeria, Sierra Leone, Algeria, Morocco and Saudi Arabia.
Kenyan President Mwai Kibaki said China has offered to help develop a second port at Lamu which will be connected to Ethiopia, Southern Sudan and Rwanda.
Correspondents said this would provide a route to export Chinese oil from Southern Sudan.
China will also help upgrade a railroad linking Kenya's Mombasa port and the Ugandan capital, said a statement from President Mwai Kibaki's office.
"For Africa to further take off, it is very important to build up the infrastructure so that African countries can conduct intra-regional trade on a massive scale," Mr Yang told reporters.
In November, China's government said it would offer Africa $10bn (£6.3bn) in concessional loans over the next three years.
Two people in Kenya died earlier today after a five-storeyed building under construction in the town of Kiambu collapsed. Four others were said to have been injured.

The incident occurred in the middle of the night, at 02:30 local time (23:30 UTC), on Sunday morning. The building was only a few metres from another building that collapsed in October of last year, killing thirty people.

The building is reported to have been condemned last year, when the authorities deemed it substandard. Preparations to demolish the building started yesterday, in accordance with a court order that required the building to be destroyed within thirty days.

One of the casualties from the accident was Maina Irungu, aged seventeen; the other hasn't been identified. People wounded by the collapse were taken to the Kiambu District Hospital. The victims were all people who lived in houses near the collapsed building. Rescue operations are still ongoing, being conducted by the Red Cross, police, and military. Officials also ordered evacuation of two buildings in the vicinity when cracks were spotted on them, according to Capital FM Kenya.

This story in itself is reflective of a major infrastructure problem in Kenya, according to the ''BBC'', China says it will give a US$7 million (£4.4m, €4.9m) grant to help fund infrastructure development projects in Kenya.