With the development of the conservation tillage technology and low disturbance soil treatment, new tillage tools like narrow or very narrow tines are applied more often. In order to provide theoretical supports for the design and optimization of tillage tools and key components, and enrich the theory system of soil-tool interaction, the very narrow tine-soil interaction was investigated, especially during the penetration process. Two tines with different cutting edge shapes were designed and a special test bed was set up based on the soil bin test bench as well. Soil failure mechanism was analyzed. The resistances of the two tines were recorded, analyzed and compared in the penetration stage. And the resistance prediction mechanical models were proposed. The mean resistance sources of the tines were found by analyzing the tines resistance mechanical models. The contact areas of the very narrow tines in different depths were measured and calculated by using the CATIA three dimensional design software, and the relationships between the resistances and contact areas were analyzed as well. Results indicated that soil failure was mainly caused by the stress field and velocity field in the soil-tine interaction. Mechanical components of soil cohesive, pressure, friction and adhesion were the main resistance sources of the tines. The forces between the tines and soil can be predicted by the soil mechanical components. The prediction models can well reflect the tendency between the resistances and the depth in the tines working processes. Furthermore, the results indicated that there was a nonlinear relationship between the resistance and soil-tine contact area with certain soil property parameters. The tine geometry parameter became an important influence factor of the resistance.