This paper proposes an innovative active coupled multimodal robot (ACMR). The unique modal conversion mechanism and active coupled mechanism of ACMR enable the robot to have two types of motion actuators, propeller and wheel, which can move smoothly and efficiently in both the air and on the ground while only using a set of brushless motor drive source. The modal conversion mechanism adopts a turbine worm drive, which facilitates the adjustment of arbitrary whirling arm shapes ranging from 0-90° and allows maintenance without power. The changes in the wheel touchdown timing, robot width, and worm driving torque during the conversion from flight mode to driving mode are theoretically deduced and simulated. The active coupled mechanism employs the combination of a planetary gear train and gear rack mechanism to achieve the active coupling between the three-claw coupler and the propeller. The kinematic relationship between the descending distance of the coupled claw and the modal conversion angle is analyzed, and the maximum descending distance is obtained.