Zhu Chengshan, memorial hall curator, said it had been the 10th year in a row since the international peace rally was held on the massacre anniversary.
"We believe it is a good practice to promote world peace," Zhu said.
Earlier in the morning, 200 monks from Buddhist temples in Nanjing and Japan braved the cold and started a mantras chanting praying ceremony in front of a "weeping wall" outside the memorial, on which the names of victims killed during the massacre are engraved.
According to documents from the memorial hall, which has collected 25,000 pieces of evidence, more than 20,000 rapes of Chinese women by Japanese invaders occurred during the massacre. More than one third of buildings in the city were destroyed by the bombardment.