The State Administration of Cultural Heritage approved the renovation plans, according to a release sent to the Global Times on Tuesday by the administration committee of the Tiananmen area on Tuesday.
Tourists can visit the square but cannot enter the tower during renovations.
Most parts of the tower are safe, but during an inspection from 2013 to 2014, inspectors found some parts of the building are suffering from water seepage and an aging infrastructure.
These problems have affected the holding of important events on the square, said the committee.
October 1, 2019 marks the 70th anniversary of the founding of the People's Republic of China. Since 2011, a giant flower basket with the theme of "Good Luck, China" has been placed in Tiananmen Square to celebrate China's National Day on October 1.
Tiananmen Square has been the site of many milestone events in Chinese history.
Nearly 115,000 visitors came to Tiananmen Square to watch its flag-raising ceremony on the National Day last year, The Beijing Morning Post reported.
The renovation will not alter the building's original structure and it will help long-term preservation, according to the release.
Tian Lin, a professor of ancient architecture at the Beijing University of Civil Engineering and Architecture, told the Global Times on Tuesday that the project went through several rounds of discussions, as the government has to make sure all these problems will be solved on time, because the tower is an important site for holding national events.
On September 3, 2015, thousands of Chinese troops, along with their counterparts from 17 countries, marched past Tiananmen Square to mark the 70th anniversary of the end of World War II and the Chinese People's War of Resistance against Japanese Aggression.
Prior to the military parade, the main facade in front of Tiananmen Square was outfitted with an explosion-proof layer.
The complexity of the construction work also makes the renovation of the Tiananmen gate tower difficult, Tian told the Global Times.
The tower was built with ancient bricks, some of which have broken as time went by, so they have to be carefully replaced, and the tower's waterproofing has to be redone, according to Tian.
First built in 1417, the gate tower was modified several times during the Ming Dynasty (1368-1644) and Qing Dynasty (1644-1911).
It underwent further renovations in 1970 to resist earthquakes and was fitted with broadcast facilities.
The broadcast facilities are another complexity since they cannot be damaged during the construction, said Tian.
He believes all these problems will be fixed on time as the plan is well arranged and the construction team is highly professional.