In this paper we propose a modeling method for the interaction impedance of a remote soft tissue that contains quasi-periodic physiological motion disturbance. Through this study, it is shown that the interaction with such environment is not passive and its influence should be considered in the teleoperator design. The interaction impedance depends not only on the soft tissue impedance but also on the relationship between the robotic tool motion and the soft tissue motion disturbance. An illustrative case study is presented to demonstrate how to analyze the environment interaction impedance in real application.