Abstract: Enteric microcapsule with insecticidal crystal proteins (ICP) of Bacillus thuringensis as core material and hydroxypropyl methylcellulose phthalate (HPMCP) as shell material was prepared by double emulsion method. Experiments in orthogonal matrix design [L16(45)] showed that the encapsulation of ICP was influenced by factors such as emulsification rotation speed, concentration of core and shell materials, emulsification agent and hydrocolloids, ranged in a pattern of decreasing importance. In 500 mL aqueous medium for formation of the microcapsule, the optimal condition was 6000 r/min of emulsion rotation, 1 mL solution of 20% IPC, 6 mg of HPMCP dissolved in 50 mL mixture of ethanol and acetone (1:1 v:v), 2 mL castor oil and 2.2-2.5%carboxymethyl cellulose (CMC-Na) in aqueous medium, where about 85% ICP was encapsulated. The microcapsule was sphericity figure in diameter of mean 20.7 μm and releaved all protein within 5 min at Ph 8.5 medium.