The treason trial will be held on Friday at the Magistrate Court Complex, Hibiscus Road, Lusaka, Zambia.
"As we celebrate Africa Day, the leader of the opposition in Zambia faces trumped up criminal charges brought against him by a government intent on reversing the gains of democracy in Zambia and in Southern Africa," said Maimane in a statement on Thursday.
Six weeks ago, Zambian Police arrested Hichilema and charged him with treason while he was on route to a ceremony in the Western province of Zambia.
Maimane said the initial “crime” Hichilema is alleged to have committed, was that he attempted to block Zambian President Edgar Lungu's motorcade which was travelling on the same road.
"However, when the state prosecutors failed to substantiate that charge, they amended the charge and alleged that Hichilema and 60 others had conspired to declare Mr Hichilema the President of Zambia, and therefore charged him with treason," explained Maimane.
Treason is a non-bailable offence in Zambia, with a minimum jail term of 15 years and a maximum sentence of the death penalty.
"The violent nature of his arrest, and the inhumane treatment that Hichilema has received in detention, confirms the political motives behind these charges," said the DA leader, who is travelling to Lusaka to attend the court case.
"The arbitrary arrest of political opponents is a hallmark of authoritarian regimes, which seek to systematically eliminate any potential threat to their rule.
"Hichilema has suffered injury in detention, and attempts we have made to visit him in prison have been blocked by the Zambian government. Even Zambia's founding President Kenneth Kaunda was stopped from visiting Mr Hichilema in prison."
Maimane said the circumstances which led to Hichilema’s arrest are an affront to democracy across the region, and point clearly to a political motivation.
"The South African government has maintained a deafening silence in this matter, despite our calls for President Zuma to intervene to stop this outrageous political trial.
President Zuma and the ANC’s silence says much about their disregard for democratic values and principles on the continent."
He said the DA will not be silent.
"We will stand up for democracy and the rule of law on the African continent and we will be there in person to show our support for Mr. Hichilema. We also call on the Zambian government to drop these trumped up charges against the Leader of the Opposition, and release him from prison."
Maimane said his party is unequivocally committed to the advancement of vibrant, competitive, multiparty democracy, the rule of law, and the entrenchment of human rights and free speech across Africa.
He said the persecution of Hichilema goes against these values, and as such we must stand in solidarity with those who are fighting for true democracy on the continent.
In this light, the lack of action by regional bodies and other African nations is a great cause of concern.
Maimane said there has not been "one word of condemnation" by the South African Development Community (SADC) and the African Union (AU).
"This silence from the regional bodies responsible for fostering democracy and unity across Africa is unacceptable," said the DA leader.
"We once again call on these bodies – and other African states committed to democracy – to condemn the actions of the Lungu administration.
"The Democratic Alliance stands by Mr Hichilema and we offer him our full support, and will attend his trial tomorrow to demonstrate our support. We call on the Zambian government to stop this ludicrous trial."