Medium chain triglycerides has the effect of reducing body weight, regulating lipid metabolism, relieving fatigue and so on, and it is liquid at room temperature. In order to facilitate its application in the field of food, the medium chain triglycerides microcapsules were prepared by spray drying with whey protein and inulin as composite wall materials. The effects of composite wall material proportion, wall material addition amount, core-wall ratio, emulsifier addition amount and composite emulsifier proportion on the embedding rate of medium chain triglycerides microcapsules were investigated by single factor experiment. Box-Behnken design response surface test was used to optimize the preparation formula of medium chain triglycerides microcapsules, and the basic physical and chemical properties of the prepared medium chain triglyceride microcapsules were determined. The response surface method results showed that the optimal preparation conditions of medium chain triglycerides microcapsules were as follows: whey protein: inulin ratio of 3∶1 (w/w), emulsifier supplemental amount of 0.4 g/100 mL, core wall ratio of 1∶1 (w/w), compound wall material (whey protein and inulin) supplemental amount of 14 g/100 mL, compound emulsifier (monoglycerol∶sodium carboxymethyl cellulose) ratio of 1∶1 (w/w), under this condition, the embedding rate of carbon chain fatty acid triglyceride microcapsules can reach 95%. The medium chain triglycerides microcapsules had good fluidity, dispersibility and solubility. The microcapsules had uniform particle size, the average particle size were 4.43 μm.