The invention relates to an instant powdery grease treating starch sodium octenylsuccinate as a wall material. The instant powdery grease comprises 30-70% by mass of the wall material, 5-60% by mass of grease, 5-60% by mass of an auxiliary wall material, 0.5-3% by mass of an emulsifier, 0.1-2% by mass of an antioxidant and 0.1-0.5% by mass of a cosolvent. The invention also relates to a preparation method of the powdery grease. The preparation method is characterized in that a microencapsulation technology is adopted to embed fat-soluble grease in order to prepare a microcapsule, the wall material used for embedding is starch sodium octenylsuccinate, the addition of the emulsifier and the addition of the auxiliary wall material improve the emulsification shear speed, improve the homogenization pressure and increase the homogenization frequency, grease is embedded in the wall material and undergoes spray drying, and the addition of the cosolvent forms the instant powdery grease. The preparation method has the advantages of simplicity and low cost, and the prepared powdery grease has the advantages of good water solubility, fast dissolving, high oil carrying amount, and good fluidity and can be applied to the food field, the daily-use chemical engineering field, the medicine field and the like.