The House began the fiscal 1988 appropriations process yesterday in familiar fashion -- by ignoring a White House veto threat and by decisively rejecting an attempt to trim spending.

The bill was the $16.1 billion energy and water appropriations measure, which cleared the House by an overwhelming vote of 340 to 81, far more than the two-thirds majority needed to override a veto.

The key test in the debate came over an attempt by a bipartisan coalition of lawmakers headed by Reps. Timothy J. Penny (D-Minn.) and Thomas J. Tauke (R-Iowa) to cut 1.7 percent, or $271 million, from the bill. The House rejected the cut, 276 to 143.

The amendment would have reduced by half the increase in spending from this year's appropriation to the level proposed for 1988. The coalition plans to offer similar proposals to trim increases in other appropriations measures to reduce spending by about $6 billion next year.

Penny and his allies argued that such across-the-board reductions would not severely damage any single program.

"It is a small sacrifice for all of us," said Rep. Nancy L. Johnson (R-Conn.). "It's tough, but not disastrous and the result will be real deficit reduction."

The House Democratic leadership countered the coalition's plan by making certain that the first test case in the budget-cutting attempts would come over a popular measure loaded with public-works projects in numerous congressional districts. Appropriations Committee members also warned that approval of the 1.7 percent reduction would only encourage other subcommittees to inflate appropriations measures to offset possible cuts on the House floor.

"You're trying to save some money while the country goes to the dogs," said Appropriations Chairman Jamie L. Whitten (D-Miss.).

"If the country is going to go to the dogs if we cut 1.7 percent, then the dogs ought to have it," replied Rep. Arthur Ravenel Jr. (R-S.C.).

Earlier yesterday, the House refused, 337 to 82, to delete $110 million from the bill for the Appalachian Regional Commission. The Reagan administration has failed repeatedly to kill the commission.

About half of the appropriations measure would fund nuclear military programs in the Energy Department. However, the House bill cut several administration requests for defense-related spending, including $84 million for nuclear weapons activities, $201 million for nuclear directed-energy weapons under the Strategic Defense Initiative and $30 million for nuclear materials production.

In a statement threatening a veto, the White House objected to these cuts, to "excessive funding" of domestic programs and to the absence of funding for the Superconducting Super Collider project.