Nowadays with more focus on pursuing digital smart farming, the curiosity for underground component portion in plant growth is developing rapidly. Obtaining real time info on plant root-soil interaction environment without damaging current habitat has been a challenge in agriculture field. In this study, we proposed a bio-inspired soft robot with auger capability allowing for an in situ measurement of plant-soil properties. We developed this pneumatic actuated multi-chamber robot and evaluated its deformation performance such as elongation, contraction and bending. We conducted a further simulation based study on auger tip mainly for steering and navigating. We examined various design factors to optimize our auger functionabilities. Greater auger spiral teeth pitch, lower auger cone diameter to height ratio under the constraint of attached robot modular size along with larger spiral teeth width to outer shape diameter ratio would increase steering efficiency and add additional penetration strength if desired in hard soil.