Thousands of Chinese troops and military vehicles will travel through Beijing to commemorate the 70th anniversary of the war's end. The parade will be overseen by Chinese President Xi Jinping and other world leaders, including Russian President Vladimir Putin.
Japanese Prime Minister Shinzo Abe, along with most other Western leaders, has declined to attend.
News that Ban plans on attending the parade prompted Japan's Foreign Ministry to express its "strong displeasure," according to Japanese media reports.
On Tuesday, Chinese Foreign Ministry spokeswoman Hua Chunying dismissed those remarks.
"At the moment the international community is commemorating the 70th anniversary of the World Anti-Fascist War, Japan's so-called protest or remarks sound very irritating, which is deliberately provocative," she was quoted as saying by Reuters.
"We hope Japan can truly face up to and deeply reflect on its history of militarism with an honest and modest attitude."
Last week, Ban said he was aware of Japan's complaints, but that it was important to recognize China's sacrifices and contributions during the war, Chinese state-run media reported.
Many people in China, as well as in North and South Korea, hold hostility toward Japan over their belief that it has failed to properly atone for wartime atrocities.
South Korean President Park Geun-hye will also attend the Beijing parade, along with a senior North Korean official, Reuters reported.