A metasurface composed of stacked double-diabolo structure was designed. By adjusting lattice period of the metasurface, hybridization between different order lattice modes and eigenmodes of the metasurface led to three strong coupling regions and two Friedrich-Wintgen BIC (FW-BIC) at two lattice periods. The analysis results based on the coupled mode theory agreed well with the numerical simulation, which further proved the validity of our structure. The strong coupling and BIC effect could be used to enhance localized magnetic field in spacer layer. The maximum magnetic field intensity was 412 09 times of the incident THz wave, and this value was 4 times comparing with the purely electromagnetic resonance of metasurface. The results provide suggestions for the study of strong field THz generation and THz nonlinear optics.