Chinese President Xi Jinping is expected to announce an investment of $46 billion in Pakistan.
The focus of the spending is on building a China-Pakistan Economic Corridor (CPEC) – a network of roads, railway and pipelines between the two.
They will run some 1,865 miles from Gwadar in Pakistan to China’s western Xinjiang region.
The projects will give China direct access to the Indian Ocean and beyond.
“Pakistan, for China, is now of pivotal importance. This has to succeed and be seen to succeed,” Reuters quoted Mushahid Hussain Sayed, chairman of the Pakistani parliament’s defense committee, as saying.
Pakistan, for its part, hopes the investment will boost its struggling economy and help end chronic power shortages.
Leaders are also expected to discuss co-operation on security.
President Xi Jinping will spend two days in Pakistan holding talks with President Mamnoon Hussain, PM Nawaz Sharif and other ministers. He will address parliament on April 21.
Deals worth some $28 billion are ready to be signed during the visit, with the rest to follow.
Under the CPEC plan, China’s government and banks will lend to Chinese companies, so they can invest in projects as commercial ventures.
A network of roads, railways and energy developments will eventually stretch some 1,865 miles.
Some $15.5 billion worth of coal, wind, solar and hydro energy projects will come online by 2017 and add 10,400 megawatts of energy to Pakistan’s national grid, according to officials.
A $44 million optical fiber cable between the two countries is also due to be built.
Pakistan, meanwhile, hopes the investment will enable it to transform itself into a regional economic hub.
Ahsan Iqbal, the Pakistani minister overseeing the plan, told the AFP news agency that these were “very substantial and tangible projects which will have a significant transformative effect on Pakistan’s economy”.
Xi Jinping is also expected to discuss security issues with PM Nawaz Sharif, including China’s concerns that Muslim separatists from Xinjiang are linking up with Pakistani militants.