President dos Santos, 74, arrived in Luanda late Wednesday, accompanied by the First Lady, Ana Paula dos Santos.
They were received at the Luanda military air base by Vice-President Manuel Domingos Vicente and other top government officials.
The veteran leader has visited the European state several times since 2013, Africa Review said.
President dos Santos left Angola on July 3 for Barcelona, with his office alluding in a statement that the visit was private, without divulging details.
He spent 28 days in Spain in May without an official explanation, prompting claims of his death on both the social and traditional media.
“He is in Spain and when he gets fine he will be back home,” Foreign Affairs minister Georges Chikoti told journalists in Luanda on May 29.
It was the first time a top government official confirmed that President dos Santos usually went to Spain for medical treatment.
“President dos Santos normally seeks medical treatment in Spain and this is normal for him to be there,” he said.
“It is all right but you know it happens with everyone. Sometimes you don’t fill fine but he is fine.”
President dos Santos has been in power since in 1979 and is Africa’s second longest serving president after Obiang’ Nguema of Equatorial Guinea.
The southern Africa state goes to the polls on August 23 that will see the long-serving leader retire.
The ruling party, MPLA, has nominated Defence minister João Lourenço as its flag bearer for the August presidential contest.
Opposition has been calling on the government to reveal the state of the President health amid reports that Africa’s second-longest ruler is seriously ill.
Dos Santos, who has run the oil-producing southern African nation since 1979, first left Angola at the start of May on what was officially billed as a two-week “private visit”.
His daughter, Isabel, took to Instagram to knock down “fake news”, that her father was probably dead.
“Someone has gone so low as to invent information about the death of a man in order to create confusion and turmoil in Angolan politics,” Isabel dos Santos, who is also head of state oil firm Sonangol, said.
Raul Danda, parliamentary president of the opposition UNITA party, said the lack of clarity about the health of the man who has been central to Angola’s stability since the end of a long civil war in 2002 was becoming a national security issue.
Dos Santos, a Soviet-trained oil engineer and veteran of the guerrilla war against Portuguese rule, rarely appears in public but the last time Danda saw him, he did not look well, he said.