The leader of India's governing Congress party, Sonia Gandhi, has met the Chinese president and prime minister in Beijing.
Mrs Gandhi is one of India's most powerful politicians
Mrs Gandhi said talks with the two men were a milestone in relations between the two countries.
Relations between the two countries have been strained by a long-running border dispute and concern in Delhi over China's close ties with Pakistan.
Nonetheless, bilateral exchanges and trade have increased in recent years.
Mrs Gandhi will also visit Shanghai and the north-western city of Xian during her five-day trip.
"I am amazed and astounded at the progress made by the people of China and its leadership," she said on Friday, according to AFP news agency.
Mrs Gandhi's trip comes nearly 20 years after she accompanied her husband Rajiv - who was prime minister of India at the time - to China on a trip which opened a new era in relations between the two countries.
On Wednesday, the Chinese foreign minister said India should play a bigger role in the United Nations, but stopped short of directly supporting Delhi's bid for a permanent seat on the security council.
Correspondents say that although the two countries talk about warmer relations, they are often locked in competition for global influence or for the raw materials and energy they need to run Asia's two fastest-growing economies.