Theodore G. Venetoulis has gained considerable ground in the Maryland Democratic primary race for governor, pulling within striking range of Acting Gov. Blair Lee III with nine days left before the election, according to a newspaper poll published here today.

The poll, commissioned by The Baltimore News American, shows Lee with a 3-to2 edge over Venetoulis the Baltimore County executive. But it also shows Venetoulis gaining support at a rapid pace, substantially narrowing the 2-to-1 lead held by Lee in the last poll published in early July.

While confirming Lee's status as the frontrunner, the poll is regarded as an important boost for Venetoulis, showing his campaign with momentum and raising the possibility of victory by attracting those in the sizeable block of still undecided voters - 34 percent of the voters polled.

Both candidates picked up support in the latest poll, which was taken between Aug. 18 and Aug. 24. But Venetoulis surged ahead at a faster pace., rising from 14 percent of the voters polled in July to 21 percent in August. Lee rose from 29 percent to 33 percent in the same period.

The other Democratic candidates in the Sept. 12 primary - former state Transportation Secretary Harry R. Hughes and Baltimore City Council President Walter S. Orlinsky - continued to lag far back in the field. Hughes received 8 percent of the vote in the latest poll and Orlinsky 4 percent.

Today's poll helps clarify the highly competitive Democratic contest as all four candidates switch into intensified campaign schedules and plans for active door-to-door canvassing, telephone and mail soliciations and saturation radio and television advertisements.

The Lee and Venetoulis camps each interpreted the poll as victories for their respective sides, claimin the results come as a morale boost for their workers and candidates and an aid in raising money for the rest of the campaign. Each viewed the poll as a sign their candidates are healthy.

"Until now," said Venetoulis' campaign manager, Jackie Smalkinson, "the thing we have had to prove is that Ted can win. People will see that poll and if they were hesitant they won't be now. It tells the undecided voter, if he wants a change, he can vote for a winner."

Smalkinson said the poll should also serve as a signal to supporters of Hughes and Orlinsky "not to waste their votes on losers." Hughes and Orlinsky are said to attract support among liberal and Baltimore voters whom Venetoulis believes should vote for him.

Joseph Anastasi, Lee's campaign manager, said he was "very happy" withe the poll. He said while "it's always nice to see yourself higher, it's nice to be in the lead." He said the results show "it's not going to be nose to nose. We're a couple of lengths ahead now."

"A good portion of the undecided vote will come to use now because we're seen as the winner," said Anastasi. He added that he is "not at all rise, saying he believes the Baltimore Countian has peaked at his present level.

Since the News American began publishing polls last spring, Lee has received support from about a third of the voters contacted by telephone. At the same time, Venetoulis' ratings have steadily climbed from 9 percent in April to 14 percent in July and 21 percent today.

Lee's inability to increase his share of the straw vote despite a very high recognition among voters and more than a year in office has heartened Venetoulis and other challengers, who now believe the large number of undecided voters will choose an alternative on primary election day.

Lee, 62, who became acting governor last August after Gov. Marvin Mandel was convicted on political corruption charges, has been running a low-key campaign emphasizing his experience as lieutenant governor. He has the backing of most of the old-line political organizations in the state.

Conceding the Lee "is not an exciting candidate," Anastazi said he was pleased that the acting governor has been able to maintain his support among a third of the voters. Along with those "hard" votes, he said, "Lee should attract enough undecided voters to win with 40 per cent of the vote.

The next week, said Anastasi, will see extra efforts by the Lee campaign to make inroads into the undecided voting bloc. More than $80,000 has been committed for radio and television advertisements. The campaign plans to reach 180,000 senior citizens with special mailed appeals.

Venetoulis, 44, who is running a "reform" campaign and calling for "New Maryland," plans to spend $40,000 in the next nine days on television and radio advertisements. He is relying heavily on a "grassroots" organization of volunteer to turn out the vote Sept. 12.

One of the surprising results of the News American poll was the low standing of Hughes, whose underfinanced, low-key campaign received a large boost in recent weeks as result of a front page endorsement in The Baltimore Sun and several successful performances on television debates.

Hughes was campaigning on the Eastern Shore yesterday and could not be reached for comment. His campaign manager and spokesman also could not be reached.

Orlinsky's campaign manager, Betty Deacon said she was not entirely disspirited by the poll and is hoped her candidate cna cut into the undecided vote. "I'm not telling you we're going to win," she said. "I'm telling you we're going to get a much higher vote than is in that poll."