In order to optimize the parameters of the nickel powder filled cement based sensors, effect of size, electrode separation and surface roughness of sensors on stress/strain compatibility between sensors and their surrounding concrete was investigated with finite element software ANSYS. The stress states of the optimized nickel powder filled cement based sensors and their surrounding concrete was analyzed when the sensors embedded in concrete. The results show that the suitable size and electrode separation of the sensors are 20mm×20mm×40mm and 5mm respectively. The surface of sensors should be as rough as possible. The sensors are nearly subjected to a uniaxial stress state when they are embedded in concrete. The stresses of the sensors and their surrounding concrete are quite different, As the strain is compatible, the testing results of sensors need to be modified for ensuring test accuracy when the sensors are used for health monitoring of concrete structures.