Abstract: Radishes were used as raw material to study on three commonly pretreatment methods including heated-air drying, blanching and high-salt pickling, activities of pectinase and brittleness were investigated.The result showed that, in the conditions of 30℃ hot-air which imitated the outside temperature in autumn, activities of pectinase of radishes rose at beginning and then declined, the brittleness of radishes declined too, changes were closely related to the water loss, losing 35% water was the optimum condition, as a result of that the brittleness dawn to 45% and the the activity of pectinase falt 20%.Different conditions of blanching had an enormous impact on the activities of pectinase.The result indicated that the optimum condition was 60℃, remaining 10min, under these conditions, as a result of that the brittleness dawn to 15% and the activity of pectinase fell 27%.Sodium concentration had significant effect on the activity of pectinase.In the low-salt condition (NaCl<4%) , pickling could increase the activity of pectinase, in the high-salt condition (NaCl>6%) , pickling could reduce the activity of pectinase.These factors taken together, pretreatment methods influenced on the activity of pectinase and brittleness.Given the influence on the activity of pectinase and brittleness by different pretreatment methods, high-salt pickling in the beginning was the best method.