Members of the Standing Committee of the National People's Congress (NPC) approved the law at the closing meeting of a legislative session on Saturday, state-run Xinhua news agency reported.
The law, which becomes operational from January 1 next year, stipulates that ''the sovereignty and territorial integrity of the People's Republic of China are sacred and inviolable'', it said.
The state shall take measures to safeguard territorial integrity and land boundaries and guard against and combat any act that undermines territorial sovereignty and land boundaries, the report said.
The law also stipulates that the state shall take measures to strengthen border defence, support economic and social development as well as opening-up in border areas, improve public services and infrastructure in such areas, encourage and support people's life and work there, and promote coordination between border defence and social, economic development in border areas, it said.
The state shall, following the principle of equality, mutual trust and friendly consultation, handle land border-related affairs with neighbouring countries through negotiations to properly resolve disputes and longstanding border issues, it said.
India and Bhutan are the two countries with which China is yet to finalise the border agreements, while Beijing resolved the boundary disputes with 12 other neighbours.
Last week, Foreign Secretary Harsh Vardhan Shringla said the developments along the Line of Actual Control (LAC) in eastern Ladakh have ''seriously disturbed'' the peace and tranquillity in border areas, and this has obviously had an impact on the broader relationship too.
The foreign secretary, in his remarks at a seminar on ''Leveraging China's Economy'' on Oct 21, also referred to External Affairs Minister S Jaishankar's remarks that the ability of India and China to work together will determine the Asian century.
''For this to materialise, peace and tranquillity in the border areas is a sine qua non. He (Jaishankar) has also clearly articulated that development of our ties can only be based on mutuality -- mutual respect, mutual sensitivity and mutual interests should guide this process,'' Shringla said.
''We hope that the Chinese side will work with us to bring a satisfactory resolution to the current issues so as to make progress on our bilateral relations keeping in view each other's sensitivities, aspirations and interests,'' the foreign secretary said.
While India-China border disputes cover 3,488-km along the Line of Actual Control, China-Bhutan dispute covers about 400 km.
The new land border law was adopted amid the continued standoff between Indian and Chinese militaries in eastern Ladakh.
On October 14, China and Bhutan signed an MOU firming up a three-step roadmap for expediting the boundary negotiations, which Beijing said will make a "meaningful contribution" to speed up the border talks and establishment of diplomatic ties.