The matching mechanical impedance between the flexible sensors and the soft gripper will endow the soft pneumatic gripper with excellent actuating performance and sensing ability. In this paper, a conductive elastomer based on Polydimethylsiloxane (PDMS) doping carbon conductive filler is proposed, which has similar mechanical properties with the body material of the gripper. The resistive strain senso was fabricated based on a conductive elastomer, and the piezoresistive sensor was assembled by two conductive elastomers with microstructures, which were used to monitor bending deformation and pressure changes, respectively. Two essential factors of the conductive filler type and the MWCNTs mixing ratio have been investigated to improve the sensitivity and mechanical properties of proposed sensors. MWCNTs with large aspect ratio has been selected as the conductive filler. The resistance strain sensor, filled with 8 wt%, displays good angular discrimination ability with a sensitivity of 0.107 kΩ/°. The piezoresistive sensor exhibits good force sensitivity within 0 ~ 350 kPa range. The sensors have been integrated into the designated area of a soft pneumatic gripper and well reflect the diameter and weight of the grasped object.