Solana arrived from Addis Ababa on Saturday, where he had announced that the EU and its member states would finance over half the cost of a boosted African Union (AU) contingent due to monitor a shaky truce in Darfur.
In Khartoum, Solana is to hold talks with President Umar Hasan Ahmad al-Bashir and Foreign Minister Mustafa Usman Ismail before leaving on Sunday.
The EU official was welcomed at Khartoum airport by Al-Tigani Al-Salih Fadil, an aide of the minister.
Solana told the official Suna news agency he wanted to see the situation on the ground in Darfur and to "know what efforts the Sudanese government is exerting to resolve the conflict."
Fadil, whose government has been in the line of international fire over Darfur, said Sudan had welcomed international cooperation in helping to resolve the Darfur crisis and other issues.
Dutch Foreign Minister Bernard Bot, whose country currently holds the EU's rotating presidency, issued a warning to al-Bashir during a visit to Sudan two weeks ago.
Threat of sanctions
He reiterated the threat of UN sanctions on the country's vital oil industry.
EU Foreign Policy chief Javier
Solana will evaluate the situation
Solana's visit comes after a mini-summit of Sudan's neighbours in Tripoli last week aimed at finding a solution to the 20-month-old conflict in the western Darfur region, in which tens of thousands of people have died and close to 1.5 million have been displaced.
AU-sponsored talks between Khartoum envoys and the two main Darfur rebel movements also kicked off in Nigeria on Friday.
The international community is demanding Khartoum take stronger action by providing security for civilians in Darfur and by assisting the humanitarian effort there.
Rebels refuse disarmament
Sudan says it has met all the requirements of the UN while the rebels, who are unwilling to be disarmed, are ignored.
Fake rape videos, rebels posing as Janjawid and rebels kidnapping people are reports that are also ignored by the international community, according to Sudan.
The UN's top envoy to Sudan is due to draft recommendations to the Security Council at the end of the month, having recently said that not enough progress had been made.
More AU troops
AU peacekeeping force in Darfur
set to be reinforced
This week the AU announced it was set to boost the number of truce-monitoring troops in Darfur from 465 to 3320, the first of which are due to arrive on Monday.
"Given the situation in Darfur, this mission has to be a success. The African Union is going to be a success with the cooperation of the international community," Solana said in Ethiopia.
However, clashes between the warring parties continue to dog peace efforts.
On Saturday, the official Sudanese Media Centre reported fighting between Sudanese government troops and Darfur rebels over the past two days.
A statement said rebels launched three attacks on troops stationed in the North Darfur town of Al-Lait Jar al-Nabi.
The SMC said government troops repelled the attacks and inflicted heavy losses on the rebels, but did not provide any further details.
In a separate incident AFP reported that 10 people were killed on Saturday when the Sudanese air force attacked a town in the south of Darfur, citing a rebel spokesman.
Rebels have warned Sudan of
violating the truce
It quoted a spokesman for the Sudanese Liberation Movement, Mahjub Husayn, said the action by Sudan was a "true declaration of war against the SLM".
He issued a warning to Khartoum regarding the attacks and a continued violation of the accords. Rebels have also requested the AU to open an inquiry into the matter.
Talks between the government and Darfur rebel groups are to resume in Abuja on Monday.