Iambic Pentameter, Rime Royal in Six Sections
(For more on Iambic Pentameter, see the "Writing Style" section of our guide to the Canterbury Tales Prologue and Frame Story.)
The "Clerk's Tale" is composed of seven-line stanzas, each stanza rhyming ababbcc. This is the "rime royal" form. Chaucer also uses this stanza form for "The Man of Law's Tale," "The Prioress's Tale," and "The Second Nun's Tale," all of which are religious tales about a pious woman, so it's likely that Chaucer viewed the rhyme royal form as appropriate for tales with a more serious moral purpose.
Another interesting stylistic feature of the "Clerk's Tale" is the way it often echoes the "Wife of Bath's Tale." The most striking example of this may be Walter's reflection that "God it woot, that children ofte been / Unlyk hir worthy eldres hem bifore. / Bountee comth al of God, nat of the streen / Of which they been engenderd and ybore" (155-158), which exactly matches the sentiments expressed by the Loathly Lady in the "Wife of Bath's Tale," right down to the level of the word choices employed.
These echoes have led some people to speculate that the "Clerk's Tale" is a response to the "Wife of Bath's Tale." To counter that tale's glorification of women's "maistrye," we have a tale here glorifying their obedience. Chaucer's more about putting lots of different arguments on the table than he is about beating us over the head and telling us which one is right.