In this article, the influences of different effective parameters on sensitivity of a magnetostrictive force sensor are investigated and then, a high sensitive magnetostrictive force sensor is designed and fabricated. Initially, the operational principles related to magnetostrictive force sensors are presented. Then, conceptual design of the sensor is illustrated and sensors geometry and applied materials are determined. In the next step, measurement of magnetic hysteresis and optimization of the magnetic properties through heat treatment are presented. To this end, magnetic hysteresis curves of not-annealed low carbon iron and annealed low carbon iron under different currents and magnetic hysteresis curve of bulk TERFENOL-D under different preloads and currents are obtained. Then, through numerical simulations using finite element method software, parameters affecting sensor sensitivity were identified and designed. Finally magnetostrictive force sensor is fabricated and its sensitivity and functional specifications are tested under different conditions. The magnetostrictive force sensor sensitivity and linearity error are found as 0.51mV/N and 2.8% FSO respectively, which is a higher value compared to similar magnetostrictive force sensors.