Peter M. Kranz, a resident of Southeast Washington, has been jobless since June when he was laid off his job teaching geology at the University of Maryland. He has been collecting $153 in unemployment, but at the end of the month, that check will stop.

Not surprisingly, he is frustrated. And when he read that the White House was considering taxing unemployment benefits as an "incentive" to get people off unemployment, he was moved to write President Reagan a letter.

"In view of the feelings of you and your staff, I should like to offer you a trade," he wrote. "I am herewith sending you my 'too attractive,' unemployment check in return for which you may offer me a job or send me your weekly paycheck. Thank you for your kind help."

With the letter, Kranz sent his unemployment check dated 12-07-82 and endorsed on the back, "To President Ronald Reagan in return for a job offer or his weekly paycheck."

Promptly, Kranz received a reply, a form letter that said, "Because the White House is prohibited from accepting monetary gifts or political contributions, we are returning your enclosure. However, the interest which prompted you to write is appreciated."

Even $153 richer, Kranz was not thrilled with the response. "I was incensed," he said yesterday. "I think it was typical of the insensitive attitude over there. Maybe my letter wasn't kind but I was just trying to make the point that being unemployed isn't cushy or easy. I'd love to have a job and I think most people feel that way. I don't think he Reagan understands that."

A White House press spokesman, Pete Roussell, disagreed with Kranz's analysis. "Needless to say the president remains concerned and sympathetic to the plight of the unemployed," he said. "He has said before and still believes that as long as there is one person unemployed who does not want to be, that's one too many."

Roussell said that while the president may not have seen Kranz's letter, he probably has seen similar ones. "He sees a representative cross section of the mail each week," said Roussell, "and I would imagine some in that tone would cross his desk."

Kranz, 38, received his PhD in geology from the University of Chicago and took a number of untenured teaching jobs before going overseas four years ago to teach servicemen. He had been back at Maryland one year when he was laid off.

His wife Peggy, whose job, planning programs with a psychiatrist for a health company, had helped pay the bills, was laid off from her job 10 days ago. "At first they told me I could work until Jan. 3," Peggy Kranz said. "Then they called me in and said, 'Sorry, we made a mistake, you go off the payroll Christmas Eve.' I thought that was nice of them."

Kranz acknowledged he fantasized a bit while writing his letter. "I had read somewhere that someone unemployed in England had written Queen Elizabeth and the queen had called her in for an interview to help her find a job. I guess the thought of something like that crossed my mind, but not for long.

"I grew up in a family where the attitude was if you got your education, that meant you had it made. A lot of people of my generation were taught that. Now, we're finding out different. There's pride involved here and there's also paying our expenses. It's hard to deal with, especially if you don't think people understand."