From Andrews to Zschau, the 81 new members of the House are a group that spells trouble for President Reagan.

Fifty-seven are Democrats, and many of them campaigned against "Reaganomics," against the administration's hefty increases in military spending and against further cuts in social programs.

Even the 24 Republicans are a far cry from the so-called Reagan Robots, the freshman Republicans who swept into office two years ago on the president's platform of slashing spending and taxes. Many of these new GOP freshmen are more moderate than conservative.

Take Democrat Mike Andrews. He's a Texan, but no Boll Weevil. The 38-year-old lawyer won a new seat in south Houston with a lot of help from blacks and the poor.

Take Californian Ed Zschau, 42. He's a Republican, but no robot. The successor to moderate Paul N. McCloskey Jr. is "our Atari Republican," joked one GOP official. Zschau founded his own Silicon Valley electronics firm.

The big bulge in freshmen next year is partly due to redistricting, which forced a number of members into early retirement and created 17 new seats in the Sun Belt. It is also the result of a backlash against the administration that knocked 26 incumbent Republicans out of office, while only three sitting Democrats were defeated.

Although 23 of the new freshman Democrats hail from southern and southwestern states, excluding California, only three of them could probably be classified as Boll Weevils, the conservative Democrats who have supported Reagan's tax and budget cuts: Richard Ray of Georgia, I.T. (Tim) Valentine of North Carolina, and Tom Vandergriff of Texas.

Nonetheless, few of the new Democrats, even those from the East and Midwest, would call themselves liberals. They are self-styled "fiscal conservatives" who pinned the deficit to Reagan, while looking to a liberal budget-balancing remedy: scale back defense increases and repeal the third year tax-cut.

As for the new Republicans, "They're not ideological per se," said Nancy Sinnott, executive director of the National Republican Congressional Committee. "They're pragmatic. They're practical."

Many of the new members are experienced politicians. Democrat Harry Reid is a former Nevada lieutenant governor. Douglas H. Bosco, who defeated Rep. Don. H. Clausen, chairs the California Assembly's Democratic caucus. Republican Herbert Bateman and Democrats Norman Sisisky and Frederick C. Boucher have served in the Virginia legislature.

Two of the new freshmen will be no strangers to Congress. Former Michigan representative Bob Carr (D) defeated Republican Jim Dunn who had ousted Carr in 1980. Likewise, in Pennsylvania, former representative Peter H. Kostmayer (D) won back his old seat from Republican James K. Coyne.

Although Jimmy Carter's coattails were hardly sought after this year, two of his former aides won seats: Ohio's Marcy Kaptur, who worked in the White House, and Esteban Torres of California, who was ambassador to UNESCO. New Jersey Democrat Robert G. Torricelli was an aide to former vice president Walter F. Mondale.

Others have Washington experience. Arizona Republican John McCain, who spent six years in a Vietnamese prison camp, was a naval liaison to the Senate. He is an executive for a beer distributor. New York's Sherwood L. Boehlert was an aide to retiring Rep. Donald J. Mitchell (R-N.Y.). New Mexico Democrat Bill Richardson worked as a House aide and for the State Department in the congressional liaison office.

Five new women, three Democrats and two Republicans, will join the House, bringing the total to 21. Besides Kaptur, they are California Democrat Barbara Boxer, a Marin County supervisor, who campaigned as a proponent of a nuclear weapons freeze; Republican Nancy L. Johnson, a Connecticut state senator who won with considerable Democratic and labor support; Nevadan Barbara Vucanovich, a conservative Republican and former aide to Sen. Paul Laxalt (R-Nev.); and Indiana Democrat Katie Hall, a black state senator and a Gary public school teacher.

Four new black members, all Democrats, join 17 incumbent blacks in the new Congress. Besides Hall, they are Missouri state Rep. Alan Wheat, the first black in recent history to win a district that is not predominantly minority or liberal; New York's Edolphus Towns, Brooklyn's deputy borough president and a former school teacher; and New York's Major R. Owens, a state senator and a former librarian.

A few of the freshmen were well known before they ran for office. Colorado Republican Jack Swigert was an Apollo astronaut. Florida Republican Connie M. Mack III is the grandson of the owner and manager of the Philadelphia Athletics.