Photonic spin Hall effect (SHE) is a potential precision measurement tool, which has important physical significance in the study of detecting the change of microstructure material′s structure parameters. The photonic SHE in nanometal films is studied using the weak measurement model. The results show that when the amplification angle takes the special value (the optimal weak measurement point) in the weak measurement, the amplified transverse shift of the photonic SHE in nanometal films can reach the maximum, which greatly improves the detection precision of the photonic SHE. In addition, the amplified shift obtained in the optimal weak measurement point can be used to determine the actual thickness of the nanometal film with higher accuracy. The experimental results coincide well with the theoretical analysis. This method provides theoretical and experimental basis for the future development of precision measuring tools.