The engineers were going to Tank, in South Waziristan - a remote region where al-Qaida-linked fighters are active - when unknown people ambushed their two vehicles, police and intelligence sources said.
Information Minister Shaikh Rashid Ahmad confirmed that two Chinese engineers were kidnapped on Saturday morning.
"Our security forces are trying to rescue them without getting them harmed," he said. He gave no other details.
An intelligence official in Tank said the Chinese engineers were accompanied by at least six security personnel.
Security forces found the engineers' Jeep and a second vehicle used by their group in Toor Manda, about 60km west of Tank, the official said.
The engineers were working on construction of the Gomal Zam dam, a project to generate electricity and store water.
South Waziristan has been wracked by violence this year, as the army has conducted a series of military operations against suspected foreign fighters and their local supporters, killing scores of them.
The area where the dam is being constructed is located about 350km west of Islamabad, the Pakistani capital.