The three-member team from the Chinese embassy here, led by Minister Counsellor Fan Fei, is in the state.
The visit is expected to be seen by the South Block as "acknowledgement and reconfirmation" of changed stance of Beijing, which has accepted India's sovereignty over Sikkim in last eight to nine years.
China had questioned Sikkim's accession to India and refused to grant visas on this ground to people from the state, even if they were listed as part of an Indian government delegation.
However, with much persistence from India, the Chinese authorities made official changes that were reflected in the Sino-Indian Memorandum of 2003, which was hailed as a de facto Chinese acceptance of the annexation. China also published a map showing Sikkim as part of India and its Foreign Ministry deleted it from the list of China's "countries and regions".
Sikkim, with Tibetan plateau in the North, was a British protectorate from 1886 until India's independence in 1947.
In 1950, a treaty signed between India and Sikkim ratified the status of Sikkim as an Indian protectorate with the Chogyal as the monarch. But differences between the Chogyal and those seeking a union with India finally led to the total collapse of the administration, and the government that came in subsequently decided to become the 22nd state of India on May 16, 1975.