The invention provides a position and attitude detection device and a position and attitude detection method for an omnidirectional mobile platform, including an omnidirectional wheel, a transmission shaft, an encoder, a bearing, a coupling, an omnidirectional wheel seat, a connecting rod, a pin shaft, and a steering rod , top plate, lead screw, linear guide, slider, hand grip, stepper motor, main control board, steering rod, connecting rod and omnidirectional wheel seat form a two-degree-of-freedom suspension system, and the omnidirectional wheel seat can wrap around the connecting rod Free rotation, the connection between the connecting rod and the omnidirectional wheel seat is a tight fit, the connecting rod is equipped with a bearing, the connecting rod can freely rotate around the steering rod, and the connection between the connecting rod and the steering rod is a tight fit, ensuring that the connecting rod and the steering rod have no shaft There is a bearing in the connecting rod to ensure the relative smooth sliding of the connecting rod and the omnidirectional wheel base. When the uneven ground causes the support reference plane of the mobile platform to be inconsistent with the support reference plane of the omnidirectional wheel of the pose detection device , Through the adjustment of the two-degree-of-freedom suspension mechanism, the full and non-slip contact between the omnidirectional wheel and the ground can be ensured.