Vice President Bush overwhelmed his opponents in a presidential straw poll Saturday at the Maryland Republican convention in Baltimore after mounting a major effort to secure the victory.

Bush, one of six Republican candidates for president listed on the convention ballot, received 643 votes. Sen. Robert J. Dole of Kansas finished second with 164 votes, followed by Rep. Jack F. Kemp of New York with 68.

Former television evangelist Marion G. (Pat) Robertson collected 42 votes, Alexander M. Haig Jr. received three votes and former Delaware governor Pierre S. (Pete) du Pont IV, one.

Bush, who declared his candidacy for the Republican nomination for president 13 days ago, sent his son George Jr. to represent him.

Bush's opponents had conceded defeat well before the convention, with some saying the voting procedures had allowed the vice president to buy the victory. They said the poll was biased toward the candidate with the biggest treasury.

Votes could be cast by anyone with one or more $30 tickets. The state party said 929 votes were cast, while attendance at the convention was placed at about 700.

Some of Bush's winning tickets were cast by residents of the Philadelphia area and Virginia, representatives from opposing campaigns said. The Bush campaign did not dispute the out-of-state vote charge.