This paper addresses the vibration isolation problem for Stewart platform by establishing a complete strut-based sensing joint space dynamics model (SSJSD), which is solely dependent on strut kinematics information. Combining modal decoupling theory, a modal PD (MPD) controller is designed in the modal space, resulting in the integrated SSJSD-MPD control strategy. The proposed control strategy avoids the measurement of six-degrees of freedom (6-DOF) motion for base platform, enabling all measurement sensing signals to be acquired from the strut-mounted sensors and facilitating practical deployment capabilities. Simulation results demonstrate that the proposed SSJSD-MPD control achieves 6-DOF base vibration isolation within the 200 Hz frequency range. Compared to the conventional MPD control based on JSD model reliant on base frame measurements, the SSJSD-MPD control exhibits stronger noise resistance. Although under base vibration isolation and dual vibration isolation conditions, the proposed control strategy preserves effective vibration isolation performance across all degrees of freedom of payload platform.