The Philippines Supreme Court dismissed legal challenges to a presidential election called by President Ferdinand Marcos, ruling today that the contest could go ahead as scheduled in February.

The justices voted, 7-5, to reject petitions challenging the constitutionality of a law that provides for the early presidential election. Ten votes were needed to overturn the law.

"There will be an election," said Justice Vicente Abad Santos, in announcing the decision. He said the seven justices who voted in favor of the election gave various reasons, including findings that the election law does not violate the constitution.

Some justices, however, apparently ignored the constitutional question and rejected the petitions on the ground that the election issue had become a "political question." Abad Santos gave that explanation for his own vote.

Marcos called the election, scheduled for Feb. 7, largely as a way of relieving U.S. pressure for sweeping political, economic and military reforms. In response to Marcos' call, the legislature passed a law that scheduled the election more than a year before his current six-year term is due to expire in June 1987.

Opponents of Marcos object that the law violates a constitutional requirement for a presidential vacancy before a special election can be held. Opposition leaders have demanded that Marcos resign before the election, both to make the poll constitutional and to prevent him from using the powers of his office to ensure his victory. But Marcos refused to resign before the voting, and 11 petitions were filed in the Supreme Court asking that the election law be struck down.

The opposition was left in a quandary, as efforts to field a unified opposition ticket succeeded and hopes that Marcos could be beaten were raised. The result, according to government sources, was that Marcos was torn between calling off the election to be certain of remaining in power and going ahead with it to avoid being seen as shying away from an electoral fight.

In any event, the opposition petitions in the Supreme Court gave Marcos the opportunity to blame any cancellation of the election on his foes.

Marcos denied this week that a Supreme Court decision to halt the election would amount to an admission of defeat by his ruling New Society Movement. He pointed out that it was the opposition that sought to have the election law declared unconstitutional.

Justices who voted in favor of the election have reputations for independence from Marcos.

Three legal luminaries, including a former vice president, a former supreme court chief justice and a former senator argued persuasively for the election yesterday.

Yesterday the Supreme Court considered a proposal to recommend that Marcos hold a referendum on public confidence in his leadership as an alternative to an early presidential election.

Justice Serafin Cuevas, who is considered loyal to Marcos, said yesterday that the court was contemplating a suggestion that a referendum be held instead of the election. He did not say who had made the proposal, but a press report this week said presidential advisers had recommended in a memorandum that Marcos intervene with the Supreme Court to have the election law declared unconstitutional, replacing it with a nonbinding referendum and an election solely for vice president.

Two Cabinet ministers angrily denied the story, which appeared in the San Jose (Calif.) Mercury News Sunday, calling it "a pack of lies" and "baseless speculation." The government has insisted that the Supreme Court is "independent" of Marcos.

Although the Marcos government argued in favor of the early election before the court, there were signs that a growing opposition bandwagon in the election campaign is worrying Marcos and his ruling party.

Political analysts said that Corazon Aquino, the popular 52-year-old widow of assassinated opposition leader Benigno Aquino Jr., presents the most serious electoral threat to Marcos in his 20 years in power.

Aquino was given a rousing welcome Tuesday by tens of thousands of people during a motorcade through her home province of Tarlac, where she told a cheering crowd that "we no longer have to be afraid" of Marcos.

Indications that Marcos is having second thoughts about going ahead with the election he called last month focused considerable attention on the Supreme Court, whose 13 justices were appointed by Marcos. One justice was absent from today's proceedings.