Disclosed are novel PH20 variants or fragments thereof with improved thermal stability and enzymatic activity of human hyaluronidase, which is an enzyme that hydrolyzes hyaluronic acid, and more particularly novel PH20 variants or fragments thereof including one or more amino acid residue substitutions in the variant having the amino acid sequence of SEQ ID NO: 3, wherein one or more amino acid residues at the N-terminus and/or the C-terminus are optionally further deleted.