Abstract: Scanning electron microscopy and transmission electron microscopy were used to characterize mesoporous silica, which was applied in preparation of immobilized bromelain. There are a number of clear superiority with simple process, mild condition and convenient operation. The concentrations of enzyme, pH and reaction time on the immobilized bromelain activity were investigeted.When conditions of the reaction were enzyme concentration of 25mg/mL, pH5.0, fixed time 22h, immobilized enzyme activity was 603U/g.Immobilized bromelain in water bath 50℃ for 60min, the enzyme activity remained more than 92% . The result indicated immobilized enzyme had higher thermal stability than esolvase. When the immobilized enzyme was continuously operated for three times, the relative enzyme activity still amounted to 38.5% for the third time.The conclusion showed that the bromelain molecules and vectors had a strong physical adsorption and the immobilized bromelain had certain reusability, though the activity was gradually declined.