Philadelphia will not be the same without Frank L. Rizzo as mayor. The Political campaigns certainly aren't.

Tomorrow voters here will pick party nominees for Rizzo's successor as mayor and for all other city offices.

Rizzo wanted to be in this race, but the electorate said no last November when it rejected a city charter change that would have allowed mayors to run for more than two consecutive terms.

That campaign was a boisterous one, marred by Rizzo's "vote white" statement and ignited by the most vigorous registeration and vote drive the black community has ever seen.

This campaign has been short on hellfire and brimstone.

The two top Democratic contenders, Charles W. Bowser and William J. Green, have pledged to unite the racially torn city.

Bowser, 48, was deputy mayor in the administration before Rizzo's. After that, he joined the Philadelphia Urban Coalition as executive director.

He learned a lot in those jobs and is often praised for his detailed understanding of urban problems. But the political watchers who credit him with urban expertise also criticize him for poor political organizing.

If elected, Bowser would be the first black mayor in a city where almost half the Democratic registration is black.

His Irish Catholic opponent has a political machine that, in comparison to Bowser's, purrs with efficiency. Green, 40, learned politics from his father, a former Democratic boss and congressman who died in 1964.

The younger Green won both of his father's jobs that year, kept the party chairmanship briefly and resigned from Congress to run a losing race for governor in 1976.

A smooth organization is his strength. But he's been criticized for lacking a thorough understanding of the city's ills and possible cures for them.

"It really is style versus substance," said one observer.

Both men take generally the same position on several issues, although Green has been criticized for being vague.

He said he can't be specific about trimming local governmental waste. Bowser said he would slice the payrolls of the mayor's and managing director's offices.

Green called for a general streamlining in the structure of city government. Bowser said he would have all city service areas conform with councilmanic districts.

Both have pledged to improve housing for poor people, fire the police commissioner and replace the school board.

Both have campaigned vigorously, but their rhetoric has been mild by Rizzo's standards.

The Republican primary has been nearly ignored in this heavily Democratic town.

David W. Marston, 36, the former federal prosecutor who gained fame when he was fired by President Carter, seems to be taking the winning of the GOP bid for granted.

This is his fourth campaign. His 1972 bid for the state House, a 1973 try for the state Senate and a drive for the Republican gubernatorial nomination last year failed.

Marston is known for his prosecutions of corrupt politicans, including some close to Rizzo.

Larry C. Greene, 32, is Marston's prime opponent. The political newcomer, a management consultant, is running hard but apparently is behind.

Neither William Green nor Bowser has sought the Democratic mayor's endorsement, although many of Rizzo's supporters are backing Green.

This has provided Bowser with the most powerful ammunition in the campaign. He had signs claiming "a vote for Green is a vote for the Rizzo team" plastered around town.

Green has denied any link with the mayor, but campaign disclosures filed last week show Rizzo backers have contributed thousands of dollars to Green, including $7,000 from the law firm of Rizzo's chief political adviser.

But even Rizzo foes are helping Green financially. He has raised four times as much money as Bowser - $946,000 to $232,452.

Bowser sees that as fuel for his charges.

"I think this is really another indication that the big-money guys are trying to buy city hall again, through Bill Green," Bowser said. But he added that the financial disclosures may help him, because the public doesn't "want their city government bought and paid for."

Charges of buying an election are not new to Green. He made them against his Republican opponent when he lost to H. John Heinz III in the 1976 Senate race. Heinz, of the ketchup company family, put about $2 million of his own money into that race.

That's a key difference, Green believes. "We all started even," he said of the mayoral campaign. "There was a competition for money and we went out and raised it."

Green's war chest is doing the job, the latest poll shows. According to a CBS survey released May 1, Green has the support of 46 percent of the Democratic voters and Bowser 26 percent.

The rest of those polled favored two candidates who have since dropped out of the Democratic primary, or were undecided.

Both Green and Bowser have run against Rizzo and lost. After winning a congressional seat previously held by his father in a special election after the father died, and being re-elected, Green lost a challenge to Rizzo in the 1971 mayoral primary.

Bowser was beaten by Rizzo in the 1975 general election when he created a third party to stop the mayor's reelection bid.

Whoever wins the Democratic contest has a built-in advantage over the Republican nominee. More than 75 percent of the electorate is Democratic and no Republican has been mayor since 1952.