In the paper,we simulate the extincti on spectra,near field enhancement and charge distribution of the new split nano-rectangle by using the finite difference time domain (FDTD).Then we investigate the formation mechanism of the Fano resonance in the split m etal nano-rectangle,the effects of structural parameters on Fano resonance peak,the change of the extinction spectra with the incident fields in different polarization directio ns.The results show that Fano resonance peak of the new split nano-rectangle can move obviously when ambient refractive index changes and the FoM can reach 11.8,this shows that the new splitting nano-recta ngle has a good sensing property.The same intensity of extinction rate can be seen in the specific infrared wavelengths wh en the incident light through the split metal nano-rectangleis in different polarization direct ions.The same extinction rate of laser intensity in different polarization directions has impo r tant application on forming uniform homogeneous attenuation for laser with diffe rent polarization angles.