Initiator modified γ-FeOOH nanoparticles (γ-FeOOH-Br) were prepared by using FeSO4·7H2O as precursor, 2-bromoisobutyric acid as surface modifier with the aids of ethylenediamine under pH=9. Subsequently, double-responsive poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) was grafted from γ-FeOOH-Br nanoparticles by surface initiated atomic transfer radical polymerization (SI-ATRP) method to obtain γ-FeOOH-g-PDMAEMA particle brushes, which were further used as a Pickering emulsifier to prepare Pickering emulsion. The obtained products were characterized systematically by SEM, TEM, FT-IR, TGA, Zeta potential, and particle size analyzer. The stability, pH and temperature response of particle brushes stabilized Pickering emulsion were studied. The results showed that the morphologies of both γ-FeOOH-Br and γ-FeOOH-g-PDMAEMA were needle-like. The size of γ-FeOOH-Br was about 700 nm long and about 50 nm wide, and the length and width of γ-FeOOH-g-PDMAEMA was increased to 710 nm and 80 nm, respectively. Due to the successful grafting of PDMAEMA onto the surface of initiator modified γ-FeOOH nanoparticles, γ-FeOOH-g-PDMAEMA emulsifier had a LCST of 35 ℃. The as-prepared Pickering emulsions were highly stable and demonstrated reversible pH and temperature dual responsiveness.