Gov. Edmund G. (Jerry) Brown Jr., who understands the media better than the media understands themselves, put his presidential campaign into an unusually sharp perspective here yesterday.

"The importance of this event," he told one of those continual news conferences that he holds these days, "is somewhere between a cat up a tree and a wreck on a freeway.

"And I hope I get as much coverage."

A few minutes later, he strode past a reporter for an afternoon newspaper who was dictating to his office over the telephone. "This press conference arose to the level of an insert," Brown said with a grin.

The remarks were made in jest. But they illustrate a couple of important factors about Brown's longshot bid for the Democratic presidential nomination.

First, they shoe Brown's understandable frustration in attracting attention to his candidacy. Against an incumbent Democratic president, and Sen. Edward M. Kennedy (D-Mass.), Brown realizes he is the odd man out in what is now a two-man race. And he desperately wants to make it a three-man race.

Second, the remarks give a hint of the flavor of the Brown campaign. It is simply different than any of the other presidential campaigns of either party. That's Brown's great strength and weakness. He is provocative. He is unconventional. And he is the only candidate in either party who is challenging the accepted political rhetoric of the day.

The trouble is that when you write down what Brown says it often doesn't make much sense to a lot of people. In part, that's because he doesn't speak in paragraphs. He speaks in images.

The image he wants to portray is that of a futurist, a political prophet who wants to "protect the earth, serve the people and explore the universe."

"What I want to do is to liven up the debate," he tells audiences. "The whole point of my campaign is to get more issues on the table.

"The old political order is eroding. Half the people don't vote," he usually adds. "The other half are very cynical about who they vote for."

Brown does provide an alternative. In a year when most presidential candidates are calling for more defense spending, tax cuts and a relaxing of environmental regulations, Brown is vehemently against any increases in defense spending, any tax cuts and any retrenchment in environmental laws. He wants to end the use of nuclear power. He says the country needs a new space program and a constitutional amendment to balance the budget.

He is the only candidate to visit a gay discotheque and Three Mile Island in his efforts to form a "new coalition" of supporters.

But almost everywhere he goes, the second-term governor if confronted with questions about the seriousness of his candidacy and ideas.

"So many people here and across the country are leery of Brown. It's the flake thing. There's a certain appeal there, but I think he underestimates the new conservatism on campus," Kirk Anderson, a junior at the University of Wisconsin-Milwaukee, said after hearing Brown speak.

It's also hard to see Brown's coalition emerging. After he spoke to 800 students at UWM, for instance, only 13 signed cards expressing an interest to work for his campaign. That night Brown drew only 14 blacks to one meeting, and 18 community activists to another.

"My Wisconsin effort is just beginning. It's like an acorn. It's small now, but it will grow into a big oak tree," Brown said later.

Like every candidate, Brown sees signs of progress as he runs, signs that quicken his pace, signs that give him a second wind.

Last week, he succeeded in being invited to a January debate in Iowa with Carter and Kennedy. This week, he was invited to a second debate in Wisconsin, an event to which Carter and Kennedy have also been invited but have yet to agree to attend.

Brown also said that his sometime companion, singer Linda Ronstadt, and two rock groups, Chicago and the Eagles, have agreed to appear in two fund-raising concerts for him, giving his campaign a much needed financial boost.

And when he visited Toran's Tropical Hut saloon here, one man with flowing white hair leaned back on his barstool and told Brown in an authoritative voice:

"I just want to say one thing. What I understand is that Kennedy won't get anywhere."

Brown softly clapped his hands. He had sensed a faltering in Kennedy's candidacy, and earlier in the week had shifted his major attack from Carter to Kennedy.

In New England, he accused Kennedy of being soft on big oil companies, and issued two radio commercials that featured actors posing as oil company executives saying that "Kennedy and Carter are both good for oil profits."

In Wisconsin, he accused Kennedy of endangering the safety of American hostages in Tehran by criticizing President Carter for allowing the deposed shah of Iran to remain in the United States.

"Senator Kennedy has become a me-too candidate. He's become a carbon copy of Carter on virtually every issue," Brown said at one rally. "Kennedy has dropped more in the last 50 days than any candidate in history," he added at another rally.

Asked about the significance of the shift in his attacks Tuesday night, Brown said, "When he's [Kennedy] down, stomp on him."

The next day, however, Brown said he wanted to retract his statement because he is still running basically against Carter.

"Kennedy was on top last month. Carter is on top this month," Brown said. "Next month it may be someone else."