A fiber coil mounting device is used in automated composite material layup equipment. The fiber coil mounting device includes a fiber coil mounting shaft with axial hollow structure, a fiber stop plate disposed on two sides of the fiber coil mounting shaft, and an anti-slide fiber coil tightening mechanism. The anti-slide fiber coil tightening mechanism includes a piston assembly disposed inside the axial hollow structure, a spring piece disposed on the piston assembly, a driving unit controlling an axial slide of the piston assembly, and a tightening unit driven by an axial force produced by the spring piece during the axial slide of the piston assembly.