Fifty disciples of Henry D. Thoreau, Class of 1837, will walk from Walden Pond to the Internal Revenue Service office in Boston today and tomorrow to protest the use of their tax money for the war in Vietnam.

At the end of their "Thoreau Walk," some of them will risk arrest by publicly refusing to pay their taxes for this year.

The walkers, supporters of the Committee for Nonviolent Action, will distribute leaflets and "Thoreau money" along the way. The "Thoreau money" will be about the size of a dollar bill and have a picture of Thoreau on one side. A statement on the other side will say, "This money is as phoney as the 'security' our defense dollar buys."

Mrs. Mrajorie S. Swann, organizer of the walk, said yesterday that she had named the walk for Thoreau since "he set the American precedent for nonviolent direct action." Thoreau was jailed for one night in 1846 for refusing to pay taxes to support the Mexican War.

After gathering for speeches on the Concord town square, the walkers will go 13 miles to Arlington Center today. They will reassemble tomorrow morning and walk down Mass. Ave to Harvard Square, arriving there about 10 a.m.