In order to obtain a high performance humidity controlling composite material, a halloysite/poly(sodium acrylate-acrylamide) (halloysite/PAA-AM copolymer) composite was first synthesized using an inverse suspending polymerization method, and the morphology, structure, specific surface area and thermal stability of the composite were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) analysis and thermogravimetry (TG). The results show that the halloysite and PAA-AM copolymer have a good combination with each other during the polymerization process. Additionally, humidity controlling behavior tests suggest that the absorption and desorption ratio of the optimal sample are 1.873 g g⁻¹ and 1.618 g g⁻¹ under the most favorable preparation parameters: a halloysite content of 4%, a neutralization degree of 90% and a mass ratio of acrylic acid (AA) to acrylamide (AM) of 7 : 1.