A year ago, Mayor Marion Barry was boasting of his plans for an aggressive campaign fund-raising drive, using the aura of incumbency to collect as much as possible for his reelection drive while choking the financial pipelines of would-be challengers.

On Monday, City Council member Betty Ann Kane became the second major casualty of Barry's financial blitzkrieg, announcing that she, like council member John A. Wilson, had been unable to raise enough funds to sustain her campaign. Meanwhile, two other major candidates, council member John Ray (D-At Large) and Charlene Drew Jarvis (D-Ward 4) have campaigns that are stalled for lack of money.

Ironically, Barry's victory on the fund-raising front has created new problems for his political organization. Barry, who wentinto office with a narrow 35 percent mandate from the 1978 Democratic primary, had hoped for a crowded field of challengers who would dilute the anti-Barry vote.

The Barry campaign now finds itself preparing for an almost certain contest of the kind its officials feared most--a virtual head-to-head battle with a strong challenger able to potentially capitalize on the strong anti-Barry sentiments, which most polls have found to be in the majority.

"Yes, it's going to be harder now," Barry said the other day. "Without Kane's candidacy, there's just that much more of the vote out there to get for somebody that might be running against me."

Ivanhoe Donaldson, Barry's campaign director, said, "We've planned all along for a worst-case situation. We knew a heads-up race would be much harder to handle and that's what's happened, so we're ready."

While Kane's departure has presented new problems for Barry, it also comes at a time when the incumbent's campaign has received a boost that many had not expected--attacks on Barry's stewardship of the city government have appeared to have limited impact.

In part, Barry's success at fending off complaints about the bureaucracy is due to recent improvement in some key city services and several highly visible clean-up and restoration projects around the city this year.

With criticism of the city's bureaucracy lessening from the high pitch it reached during Barry's first three years in office, strategists for Barry and lawyer Patricia Roberts Harris are now trying to put to the voters a different question: Does Barry deserve to be reelected? Is there evidence that Harris could do a better job?

Barry says, "If there's no proof that anyone can do it better, logic teaches you that you don't change. This city learned from Jimmy Carter's 1980 election that change doesn't necessarily mean improved, and new doesn't mean better. We got Ronald Reagan."

A key Harris strategist says, "I don't think most voters will tell you that this city has reached its full potential, and I think they'll vote for a change for the better . . . . The strategy Barry is forced into now is a Jimmy Carter 1980 position--'I don't have enough good to say about myself, so I'll say bad things about my opponents.'"

According to two of Harris' strategists, her basic approach will be twofold. The first will be to stress her administrative experience as former secretary of Housing and Urban Development and of Health and Human Services.

Harris also plans to remind voters of what she believes has been the inefficient operation of the city government for most of Barry's term despite election-year improvements.

Meanwhile, Barry's supporters plan to direct their campaign at Harris, touting Barry's experience as mayor of the city for the last four years and suggesting that Harris will have to learn the city if she is elected. One campaign slogan being discussed is "Experience is the Difference."

Both Ray and Jarvis have trailed far behind Barry and Harris and slightly behind Kane in the early polls. Ray has raised nearly $300,000, almost as much as Harris, but his contributions have slowed dramatically in recent months and he has reported little cash on hand. Jarvis has raised only $28,000. Barry, meanwhile, has collected nearly $700,000.

Jarvis, who has finished lowest in the polls among the major candidates, said yesterday, "I'm going to benefit with more people giving me money. Political campaigns are like a sport. Some people like to bet on the dark horse, something like a long shot, but a candidate who has a good track record."

Ray could not be reached for comment.

"John and Charlene are going to have to prove that it isn't a two-horse race," Wilson said. "The burden is on them. Now all the remaining money is flowing right into Pat Harris and the mayor. All the support and volunteers follow that momentum . . . They have to prove they are still in the race."