The shooting took place in the mountainous district of Kech on Friday, when soldiers from the paramilitary Frontier Corps (FC) were on a routine patrol, officials said.
"Six FC men embraced martyrdom while 14 others were wounded in the gun attack," Zahoor Buledi, provincial information minister, told AFP.
A top official from the FC acknowledged the assault and said that a search operation is underway in the area.
The separatist Pakistani group the Balochistan Liberation Army (BLA) claimed responsibility for the attack.
Balochistan has long been plagued by an insurgency by nationalist and separatist groups who seek to secure bigger shares in regional resources.
China, which neighbors Pakistan, is a close ally and the country's main benefactor. It launched a project known as the China-Pakistan Economic Corridor (CPEC) to connect the Pakistani port of Gwadar to China’s Xinjiang via a vast network of highways and railways.
The assault comes less than a month after three assailants from the BLA attacked the Chinese consulate in Pakistan's southern city of Karachi, leaving four people dead.