40%～50%。 The release of microencapsulated sulphite was evaluated at different types and quantities of wall materials and relative humidity. The release under different relative humidity was analyzed by Avrami’s equation. The result showed that under RH 85% SO2 retention of microencapsultion used EC as wall material was 16.2% after 6d, and used other wall materials was 8.0%～13.8% after 24d；the effect was not obvious with different wall material quantity on release; the release rate of core material under RH 85% was 1.3 times of which under RH 75% and was 5.5～7.0 times of which under RH 43% when microencapsulation used the same wall material; the injury rate and the row rate were lower about 60% respectively and SO2 residue in grape lowered 40%～50% when microencapsulated sulphite preservative on storability for Muscate Hamburg than ordinary sulphite powder or sulphite table. 