The effect of the thickness ratio between La2Ce2O7(LC) layer and YSZ layer on the thermal shock performance of La2Ce2O7/YSZ double-ceramic-layer thermal barrier coatings was studied by experimental and numerical method. The thermal cycling test indicates that with the decrease of the thickness ratio, the lifetime of double-ceramic-layer thermal barrier coatings is improved obviously and the failure region is gradually transferred to the sample center. Meanwhile the separation position is transferred from the LC/YSZ interface to the inner LC near the upper surface. The numerical results show that the lager axial tensile stress and shear stress of the interface of LC layer and YSZ layer at the edge leads to the spallation failure at the coating edge. The larger radial tensile stress at the central area of the LC surface leads to the initiation of vertical cracks accompanied by the interface deflection, which is the reason why the coating is peeled off from the inside of the LC layer.