Cherif Chekatt was killed on Thursday by police on a city street after he opened fire on officers.
Three people died following the shooting at the market and several more are seriously injured.
Interior Minister Christophe Castaner is due to attend the reopening.
Strasbourg's mayor Roland Ries said security would be tight: "We have restricted the number of entrances with checkpoints, body searches and bag searches. We have reduced [the number of entry points] for greater control, with a better distribution of police forces," he told French radio.
Strasbourg markets itself as the "capital of Christmas", and its festive market is a magnet for tourists, attracting two million visitors every year.
The city had been in lockdown after the attack while more than 700 police and soldiers hunted down the suspected gunman.
Chekatt, 29, had a string of criminal convictions in France and Germany and had become a radical Islamist in jail.