Abstract: n this paper, octenylsuccinate starch sodium, emulsifying starch, maltodextrin, β-cyclodextrin, liquid paraffin as wall materials, eucalyptus volatiles (ç TERPINENE and DL-LIMONENE) as the core material, were prepared for eucalyptus volatiles microcapsule emulsion. The factors which affect particle size distribution and encapsulating rate of the emulsion microcapsules, such as the proportion of the wall materials, the proportion of wall materials and core materials, the shear velocity etc, were studied. The results showed that the optimum preparation condition was microcapsule emulsion formula: starch sodium octenyl succinate: emulsion-809 starch: gelatin: maltodextrin: β-cyclodextrin=15:5:0:3:2, the wall material and core material ratio of 10:1, the shear rate of 10000 r/min, shearing time 2 min, high homogenization pressure of 20 MPa, homogeneous time 2 min, the second homogeneous with 10 g liquid paraffin, homogenization pressure 20 MPa, the second homogeneous time of 4 min. Encapsulated eucalyptus volatiles extended their evaporation rate, sustained release effect more than 30 days indoor.