The invention discloses deep-fried chicken steak filled with cheese and a preparation method thereof. The deep-fried chicken steak filled with cheese is prepared from the following raw materials: chicken breast, Mozzarella cheese slices, marinade, cream materials and a coating flour material, wherein the marinade is prepared from the following raw materials in parts by mass: ice water, edible salt, white granulated sugar, composite phosphate, chicken essence seasoning, ethyl maltol, salad oil, aginomoto, soybean sauce, five-spice powder, multi-spice powder, ground ginger, onion powder, groundblack pepper, potato starch, corn starch, vegetable oil, chili powder, garlic powder and white pepper powder. The deep-fried chicken steak filled with cheese prepared by the marinade in a scientific proportion has crispy exterior and tender meat quality, and cream is molten in in the mouth since cheese is molten when being heated. The components in the composition are synergized to form unique taste and flavor; and the preparation process is refined and controllable, and is favorable to realizing industrial production; and cost is effectively controlled on the premise that flavor and quality are guaranteed.