In a statement, the president says he wants the fighting between government forces and the Rwanda-backed rebel group M23 to cease by midnight on Sunday.
Lourenço is hosting the direct talks that will begin in Angola's capital Luanda on Tuesday.
"The ceasefire should include all possible hostilities against the civilian population as well as the capture of new positions in the conflict area, with the expectation that these and other initiatives will lead to a relaxed climate that promotes peace talks", writes the president's office.
According to the UN, M23 receives support from around 4,000 soldiers from Rwanda. The group took up arms against the government in Kinshasa in 2021 and has since then taken large areas of land in the mineral-rich and war-torn eastern Congo.