Abstract: Using the tools of Hausdorff dimension and Hausdorff measure, we give quantitative version for the set of admissible kneading sequences to unimodal mappings. It is proved for the set that the Hausdorff dimension is 1 and the 1-dimension Hausdorff measure is zero in one-sided symbolic space with two symbols， which are more profound than those obtained by traditional qualitative analysis.

Key words: unimodal mapping, kneading sequence, Hausdorff dimension, Hausdorff measure