The Justice Department claims in its suit that the controversial Arizona lawman refused for more than a year to turn over records in an investigation into allegations his department discriminates against Hispanics.
"It surprises me because our lawyers have been meeting with the Justice Department officials the last week and we were cooperating," Arpaio told Fox News' Neil Cavuto. "Now all at once, I'm being sandbagged and they're suing me."
The lawsuit calls Arpaio and his office's defiance "unprecedented," and said the federal government has been trying since March 2009 to get officials to comply with its probe of alleged discrimination, unconstitutional searches and seizures, and having English-only policies in his jails that discriminate against people with limited English skills.
Arpaio had been given until Aug. 17 to hand over documents it first asked for 15 months ago.
Arpaio's office had said it has fully cooperated in the jail inquiry but won't hand over additional documents into the examination of the alleged unconstitutional searches because federal authorities haven't said exactly what they were investigating.
Arpaio questioned why the lawsuit was being filed now.
"It's been a year and half they've been investigating me and my office for alleged racial profiling. Nothing has happened. But why now?" he told Fox News. "They sued the state two months ago. They just filed another suit against some county schools. And now here I'm being sued."
"So I think there's a move afoot to go after Arizona because they don't like us enforcing illegal immigration laws," he added. "So they're really going after the people of Arizona. The people of Arizona want something done and now they're zeroing in with these lawsuits."
It's the latest action against Arizona by the federal government, which earlier sued the state to stop its strict new immigration law that requires police officers to question people about their immigration status.
"The actions of the sheriff's office are unprecedented," said Thomas Perez, assistant attorney general for the department's civil rights division. "It is unfortunate that the department was forced to resort to litigation to gain access to public documents and facilities."
The lawsuit was filed in U.S. District Court in Phoenix and names Arpaio, the Maricopa County Sheriff's Office and the county.
Arizona's new law -- most of which a federal judge has put on hold -- mirrors many of the policies Arpaio has put into place in the greater Phoenix area, where he set up a hot line for the public to report immigration violations, conducts crime and immigration sweeps in heavily Latino neighborhoods and frequently raids workplaces for people in the U.S. illegally.
Arpaio believes the inquiry is focused on his immigration sweeps, patrols where deputies flood an area of a city -- in some cases heavily Latino areas -- to seek out traffic violators and arrest other offenders.
Critics say his deputies pull people over for minor traffic infractions because of the color of their skin so they can ask them for their proof of citizenship.
Arpaio denies allegations of racial profiling, saying people are stopped if deputies have probable cause to believe they've committed crimes and that it's only afterward that deputies find many of them are illegal immigrants.
The sheriff's office has said half of the 1,032 people arrested in the sweeps have been illegal immigrants.
Last year, the federal government stripped Arpaio of his special power to enforce federal immigration law. The sheriff continued his sweeps through the enforcement of state immigration laws.
Last year, the nearly $113 million that the county received from the federal government accounted for about 5 percent of the county's $2 billion budget. Arpaio's office said it receives $3 million to $4 million each year in federal funds.
In a separate investigation, a federal grand jury in Phoenix is examining allegations that Arpaio has abused his powers with actions such as intimidating county workers by showing up at their homes at nights and on weekends.
The Associated Press contributed to this report