The detection range of the PCF-SPR refractive index sensor reported in the past is generally narrow, and the detection of low refractive index cannot be realized, and the wavelength is mostly concentrated in the visible waveband or communication waveband, which limits the application range of the sensor. In view of this, an SPR sensor based on D-shaped dual core PCF structure is proposed. Indium tin oxide is deposited on the polished surface of D-shaped PCF as plasma material, and the theoretical model of the sensor is analyzed, including the influence of metal parameters on sensing performance and the influence of PCF structure parameters on sensing performance. The results show that the sensor can achieve an ultra-wide detection range with a refractive index of 1.27~1.39. Its working wavelength is in the near-infrared region of 1300~2600nm, the highest sensitivity can reach 35000nm/RIU, the resolution is 2.85×10-6 RIU.The ultra-high sensitivity and ultra-wide refractive index detection range of the sensor can be applied to the detection of plasma, white blood cells［WBC］, Hemoglobin［Hb］, intestinal mucosa of huma, human liver, acetone and other biological tissues, as well as in the fields of medicine and chemistry.