The work on two Karachi nuclear power projects with a cumulative capacity of 2,200 megawatts is underway, reported Radio Pakistan.
The power plants are being completed under China-Pak Economic Corridor (CPEC) at a cost of over Rs9 billion.
These power plants are expected to start producing electricity by the end of next year.
Similarly, work on 1,320-megawatt coal based power plants at port Qasim in Karachi and 1,320-megawatt coal based power project at Thar is also underway.
Beijing is investing around $50 billion in Pakistan as part of a plan unveiled in 2015 to link its far-western Xinjiang region to Gwadar port in Balochistan with a series of infrastructure, power and transport upgrades.
Officials expect a huge uptick in trade between the two nations once Gwadar is functional and work on motorways is finished allowing goods to cross the Himalayas to and from China's western Xinjiang province.
Deepening political and military ties between Pakistan and China have helped closer financial integration, too, with Chinese companies starting to buy Pakistani firms and land.