The Justice Department has recommended that President Reagan order former Maryland governor Marvin Mandel released from federal prison in January, four months before his term is scheduled to end, according to administration sources.

The recommendation, which calls for Mandel to be transferred first to a prerelease center in Maryland, is the administration's first response to Mandel's last-ditch effort to win presidential clemency. The recommendation was sent last week to the office of White House Counsel Fred Fielding.

A White House spokesman declined to comment last night on the status of Mandel's bid for early release.

Reagan has the final word on the granting of executive clemency, one of the most unrestricted presidential powers. Still, the Justice recommendation is considered crucial to Mandel's quest for early release. A Justice recommendation against clemency would have made White House consideration of early release less likely, according to sources familiar with the process.

Of the six codefendants convicted in 1977 of federal mail fraud and racketeering charges, Mandel is the only one still in prison.

Mandel's wife Jeanne, who has lobbied tirelessly for his early release, learned of the Justice Department recommendation last evening.

"I feel like rejoicing," she said. "It's the light in the dark I've been looking for, the turn in the road that had to come. Sooner or later, something had to happen with this man."

"My God, it's time we had equal justice," she added. "I had prayed I'd have him home for Thanksgiving; well, now maybe for Hanukah."

The former Maryland governor, who has served more than 18 months at the federal prison camp at Eglin Air Force Base in Florida, has exhausted all other means for early release, having appealed for an earlier parole date all the way up the U.S. Parole Commission. The commission ordered last year that he remain in prison until next May 14, in essence serving almost his entire term. That order came despite recommendations by federal prosecutors that he not be forced to remain imprisoned for the full period.

The parole commission's action set off a drumroll of protest from Mandel and his supporters. In an interview at Eglin a year ago, the former governor asserted that the federal parole system puts a prisoner through a second trial once he is in prison. "In spite of what the judge might have done, who heard all the details, you go through another trial, and if the parole board decides the judge didn't give you enough time, they make you serve the full sentence," he said.

Back in Maryland, friends began to orchestrate an elaborate effort to win Mandel's early release. A flurry of letters went to the parole commission and the White House calling for an earlier parole date. At least one Mandel supporter, former Baltimore Police Commissioner Donald Pomerleau, personally visited a White House aide to try to seek help for Mandel.

Annapolis lawyer Bruce Bereano was brought into the case specifically to work for Mandel's release. He charged that the commission's treatment of Mandel was "discriminatory" in light of paroles granted to other prominent officials convicted of crimes involving public corruption.

Bereano's efforts culminated early this fall with the filing of the formal request for clemency and the enlistment of a pair of powerful and unlikely allies, Sen. Paul Laxalt (R-Nev.) and Rep. Jack Kemp (R-N.Y.).

Laxalt, who, according to an aide "sees no useful purpose in Mandel serving out his entire term," agreed to deliver to the White House a petition supporting the president's use of executive clemency in the case. Kemp spoke to presidential counselor Edwin Meese III and Fielding about the request.

The petition supporting the clemency request was signed by most members of the Maryland congressional delegation and wide variety of influential Republicans. Sen. Paul Sarbanes (D-Md.) and Sen. Charles McC. Mathias (R-Md.) also sent letters to Reagan supporting the request.

Meanwhile, the formal clemency petition was reviewed first by the Justice Department's pardon attorney office and then by the attorney general's office before being sent to the White House.