In order to detect DNA hybridization with label free and high sensitivity, a hybrid alternative plasmonic slot waveguide (HAPSW) biosensor based on silicon-on-insulator (SOI) is proposed and analyzed. The reported design increases the light interaction with the sensing region by using a slot-waveguide along with titanium nitride as an alternative plasmonic material. The suggested biosensor can detect the slightest change in the analyte refractive index with high sensitivity due to an ultra-high optical confinement in the low-index regions caused by the high index contrast and plasmonic enhancement. The effective index, normalized power confinement, and sensitivity are analyzed for the detection of the DNA hybridization. The simulation results are obtained using full vectorial finite element method (FVFEM). The suggested biosensor has high sensitivity of 1190 nm/RIU (refractive index unit) for DNA hybridization detection, which is very high relative to those reported in the literature to the best of our knowledge.