Abstract: In this study,phenylalanine ammonia lyase(PAL) was encapsulated by in polyallylamine-mediated biomimetic silica. The conditions for the preparation of encapsulated PAL were optimized. Moreover,stability of the encapsulated PAL was examined. The optimal activity recovery(70%) of PAL were achieved when 0.06 m L polyallylamine(PEI) of 6 mg/m L,2 m L tetramethoxysilane(TMOS) of 1 mol/L and 1 m L PAL(2 U/m L) in 25 mmol/L phosphate buffer(p H7.0) were used. Compared with free PAL,the encapsulated PAL showed better properties in p H,thermal and storage stabilities,as well as the tolerance abilities against denaturants. In additional,the encapsulated PAL still retained 40% of its initial activity after consecutive 5 cycles.