The House Democratic leadership won key procedural votes yesterday that linked President Reagan's proposed $100 million aid package for the Nicaraguan rebels to the 1986 supplemental appropriations bill.

To cries of outrage from Republicans, the House, by a vote of 221 to 202, adopted ground rules for today's debate on the aid package that will automatically incorporate it into the appropriations bill if the spending measure is passed later this week. Only one Republican -- Rep. Bill Green (N.Y.) -- supported the ground rules, but this display of party unity could not overcome the largely united Democratic majority.

A second vote on the issue was much closer, but the Democrats still prevailed, 212 to 208.

The Reagan administration charged again yesterday that this procedure could doom its plan to provide $70 million in military aid and $30 million in nonlethal "humanitarian" assistance to the counterrevolutionary rebels, known as contras. The administration asserts that the aid will reach the contras too late if it is held up until the appropriations bill is finally enacted by Congress, and that Reagan may veto the spending measure because of objections to many of its provisions.

In a last-minute appeal to the House, Reagan tried yesterday to link the contra aid issue to the United States' military confrontation with the Libyan regime of Muammar Qaddafi. Speaking to the American Business Conference, Reagan said:

"I would remind the House voting this week that this arch-terrorist [Qaddafi] has sent $400 million and an arsenal of weapons and advisers into Nicaragua to bring his war home to the United States."

Democratic leaders quickly rejected any link to Libya or Reagan's decision Monday to order U.S. air strikes against Libyan targets. "They are two completely different matters," said House Speaker Thomas P. (Tip) O'Neill Jr. (D-Mass.).

Defending the controversial ground rules, Rep. David E. Bonior (D-Mich.) noted that the House defeated the contra aid package on March 20 and under normal procedures would not reconsider it in this session.

"We have bent over backwards to allow the president's position on contra aid to reach the floor of the House again," he said.

Under the ground rules, the contra aid package could be separated from the appropriations bill only if the spending bill is defeated by the House later this week. Republicans acknowledged that this is unlikely.

House Minority Leader Robert H. Michel (R-Ill.) called the appropriations bill "a great, rancid barrel of pork," filled with measures of importance to various lawmakers.

"There hasn't been so much pork seen in one place since the last Porky Pig film festival," Michel said.

House Minority Whip Trent Lott (R-Miss.) said the rule adopted for the contra aid debate "is one of the most blatantly cynical and transparently political that I have ever seen."

The second round of the contra aid battle on the House floor today will focus on the substance of the aid package rather than procedural issues.

House Republicans will offer a slightly modified version of the administration proposal that the Senate narrowly approved on March 27.

This measure would authorize the immediate release of $25 million in aid to the contras that could be used for military training, logistical support and the acquisition of "defensive" weapons such as surface-to-air missiles. The remaining $75 million in aid would be automatically released in July if Reagan certified that efforts to begin peace negotiations had failed.

The main battle is expected to be over an amendment to the administration plan sponsored by Rep. Dave McCurdy (D-Okla.). The proposal would also authorize the immediate release of $25 million in aid but prohibit its use for the purchase of weapons.

The McCurdy measure would also require a second, affirmative vote by Congress in late July to release the remaining $75 million if peace negotiations failed. This provision is designed to prevent Reagan from gaining the release of the funds through the veto of a congressional disapproval resolution.

If the McCurdy proposal is adopted, there appears a chance that the entire contra aid package could be defeated on final passage today by a combination of Republicans who oppose additional limits on use of the aid and liberal Democrats who oppose any aid at all to the contras.