During the meet Kim Jong-un will be elevated as the country's supreme leader. The 33 year-old is expected to use the congress to cement his leadership, declare North Korea a nuclear state.
Vigil has been tightened while free movement in and out of the capital has also been forbidden. Al these measures have been put into force to minimise the risk of "mishaps" at the event.
He is also expected to outline his vision for the nation's economic and military future.
Kim Jong-un was anointed as marshal - the highest military rank in North Korea in 2012.
The UN Security Council has strongly condemned North Korea's test-firing of a missile, saying that the launch violated UN resolutions even if it was a failure.
China has also imposed restrictions on trade with North Korea, a move in line with new United Nations sanctions on Pyongyang in April. China has decided to stop import of North Korean coal, goal and sales of jet fuel under UN sanctions, reported the Independent.