[Objective] The paper was to investigate the resistance of Tribolium castaneum to phosphine in Hainan Province. [Method] Using the measurement method of phosphine resistance of stored grain pests recommended by FAO, the phosphine resistance of eight strains of T. castaneum, adults in Hainan Province was determined. [Result] The resistance coefficients of different strains of T. castaneum against phosphine ranged from 612 to 1 045, and all strains reached extremely high resistance level (Rf > 160). When the concentration of phosphine was 200 mL/m³, ff/612, ff/826.4 and Rfl 045 strains had complete lethal time of 8, 9 and 11 d, respectively. [Conclusion] T. castaneum in Hainan Province had very strong resistance to phosphine, and the operation scheme of low concentration and long duration should be adopted in elimination of T. castaneum. [ABSTRACT FROM AUTHOR]