NOVELTY - Preparing termite preventing agent, comprises e.g. drying Eucalyptus skin, grinding into powder, mixing into 10-30 wt.% mirex and acetone (balance), formulating into insecticide solution, where in the weight ratio of Eucalyptus skin powder and insecticide solution is 5-1:1, placing in three necked glass reactor, where the volume is 2/3 of the reactor volume, stirring at 100-300 revolutions/minute for 10-30 minutes, simultaneously heating the bottom of the reactor with water bath at 60-75 degrees C, mounting an agitator at the top middle of reactor.    USE - The method is useful for preparing termite preventing agent (claimed).    ADVANTAGE - The method uses recycling device, which saves resource; and is environmentally friendly. The agent avoids other additional control work.    DETAILED DESCRIPTION - Preparing termite preventing agent, comprises (i) drying Eucalyptus skin, grinding into powder, (ii) mixing 10-30 wt.% mirex and acetone (balance), formulating into insecticide solution, where in the weight ratio of Eucalyptus skin powder and insecticide solution is 5-1:1, (iii) placing in three necked glass reactor, where the volume is 2/3 of the reactor volume, stirring at 100-300 revolutions/minute for 10-30 minutes, simultaneously heating the bottom of the reactor with water bath at 60-75 degrees C, mounting an agitator at the top middle of reactor, port stoppers at two side walls, connecting another port to condenser inlet using a hose, where condenser comprises 10-15 degrees C cold water for condensing reflux, stopper is provided at the top of the condenser, lower end of condenser and acetone collecting container is connected in a sealed manner, (iv) adding aqueous solution of gelatin from the side stopper port of reactor, where in the solid content is 20-60 %, temperature is 60-70 degrees C, amount of aqueous solution of gelatin and Eucalyptus skin powder is 1-3:1, stirring at 50-200 revolutions/minute, simultaneously cooling bottom of the reactor to 20 degrees C at the rate of 1 degrees C/minute and filtering to obtain gelatin packaged with mirex Eucalyptus skin powder crude capsule, (v) drying crude capsule to moisture content of 30-50%, placing solid content of 20-40% in gelatin aqueous solution at 35-50 degrees C, where the weight ratio of crude capsule and gelatin aqueous solution is 1:1-5, stirring at 50-80 revolutions/minute, simultaneously cooling bottom of the reactor to 20 degrees C at the rate of 1 degrees C/minute and filtering to obtain refined capsule, and (vi) drying to moisture content of 70-90%, placing in acetone, washing for 3 times and drying to moisture content of below 10%.