We present a novel simulation and design of a high-performance biosensor, which incorporates slotted Bragg-grating-based Fabry–Perot (FP) resonator structure in the silicon-on-insulator material. The device has a length of 30 um and width of 1 um, which offers a great potential for the realization of an integrated sensor array.With the combination of slot waveguide and grating FP cavity, good sensing performance can be obtained. The effect of some key structure parameters, i.e., the number of Bragg grating grids, the cavity length and slot width, on the device properties are investigated carefully. The sensitivity of 624 nm/RIU is almost nine times that of the conventional micro-ring sensor. The wide free spectral range of 23.7 nm, extinction ratio of 14.2 dB and high quality factor of 676.5 efficiently meet the requirements of high sensitivity and wide-range measurement. Also the novel biosensor shows good sensing performance with different organic solutions. All the results indicate that this device is a great promising technology platform for future biochemical sensor applications.