The invention relates to the technical field of laser-marked polymer materials, in particular to a laser-markable halogen-free flame-retardant nylon composite material and a preparation method thereof. The nylon composite material includes nylon resin, halogen-free flame retardant, flame retardant synergist, laser marking powder, black masterbatch, adsorbent, glass fiber, antioxidant and lubricant, so that the obtained nylon composite material has the following characteristics: It has excellent flame retardancy and high temperature and high humidity resistance, good tensile strength and bending strength, and good laser marking effect. In addition, the material has a simple preparation process, is environmentally friendly and clean, and has low cost, and can be directly laser marked in the product processing process to realize continuous and automatic industrial production.