War-torn Lebanon would like to see American business executives interested in investing money as well as the U.S. marines who now are on duty, participants in an investment seminar here indicated.

The Lebanese held the seminar last week for representatives of 30 U.S. companies, outlining opportunities for making money in Lebanon, and they are planning to take representatives of 50 to 75 U.S. firms to Lebanon in early November to see for themselves how open that country is for foreign investment. The nation is seeking investment in hospitals, telecommunications, data processing, construction, defense and even tourism.

"We're after American businesses. We want American businesses to go to Lebanon. It's worth it because we are confident the peace is going to come back to Lebanon," said Ambassador Abdullah Bouhabib, who boasted of his country's banking system and of the entrepreneurial skill of its "energetic, resourceful" people.

He acknowledged "some political risk for any businessman to operate in Lebanon," but said Americans who come in now "will reap the benefits of this risk." He suggested that Americans "will make more money being a partner of a Lebanese than alone."

His optimistic statements sounded familiar to a correspondent who was in Beirut in 1977, at the end of the civil war. At that time, government officials constantly sounded the theme of the rebuilding of Beirut--which, in fact, occurred to some degree until the once-beautiful Mediterranean city was devastated a year ago by an Israeli siege.

Despite continued internal upheaval, however, the country managed to prosper. Bank deposits increased as Lebanese scattered throughout the world sent money back to their country, and Westerners, including some Americans, placed money in Lebanese banks to escape taxes. There was no run on the Lebanese banks during Israel's invasion of the country.

Between the end of the civil war and the Israeli invasion, land values soared, rents moved out of sight, and building boomed.

Joyce R. Starr is the Mideast representative for Georgetown University's Center for Strategic and International Studies and head of the U.S. Business Commission on Reconstruction in Lebanon. Starr is setting up the November business tour of Lebanon in conjunction with Lebanon's Council for Reconstruction and Development. The seminar was arranged by Washington attorney Lester S. Hyman and Beirut attorney Mansour Eid.

Unlike many Third World countries, Lebanon is extremely friendly to the United States, Bouhabib said. Moreover, he said the country itself is rich and doesn't need aid, although the government--which for almost a decade since civil war broke out in 1974 has been unable to collect taxes or customs duty--is broke.

"So we'll need some money from friendly countries for the next three or four years. But we won't need money for more than a short period. We will not be a burden on the United States as long as we get our sovereignty back," he said.

He said Lebanese understand that business will invest in Lebanon for profit, not love, and added: "We know that. We're good at making money," which is why everywhere you go--the Middle East, Africa or Asia--"you see a Lebanese with a business connection," Bouhabib said.