Hyperbranched polyurethanes (HPUs) were synthesized from isocyanate end-capped poly(1,4-butylene adipate glycol) and diethanolamine via oligomeric A(2) + bB(2) approach. The structures of the resulting polymers were characterized by FT-IR, C-13 NMR. The degree of branching (DB) was calculated according to the C-13 NMR spectra. The properties of HPUs were investigated using differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), adhesion strength tests. It was found that the thermal stability of the HPU decreased with the increase of hard segment content. The HPU could be used as hot melt adhesive, and the maximum lap shear strength was up to 6.84 MPa.