A novel fiber grating radial pressure sensitivity enhanced scheme,which is encapsulated with ethylenevinyl acetate copolymer (EVA),is presented.The fiber grating is encapsulated into a half dumbbell-shaped sensing unit with EVA material and square steel.And the structure stress distribution and radial pressure response characteristics of the sensor are calculated theoretically with finite element software.Finally,an experiment system is established for verifying the sensing characteristics of the sensitivity enhanced optic fiber grating radial pressure sensors.The experiment results show that when the radial pressure is ranged from 0 to 0.3 N,the encapsulated sensors have excellent linearity to radial pressure.And the sensitivity is 100.74 times higher than that of naked optical fiber grating.Further more,after demodulation with the matching method,the sensitivity of the system can be up to 0.94 nm/N.The research results have an important reference significance for solving the practical engineering requirements for accurate measurement of micro radial strain.