For personalized rehabilitation or sports training, it is necessary to monitor dynamic motions and track postures of human body and limbs. Traditional methods using micro inertial sensors usually suffer from drift problems in tracking dynamic motions. In this paper, a wearable flow-MIMU human motion capture device is proposed by incorporating micro flow sensor with micro inertial measurement unit (MIMU). Motion velocity is detected by a micro flow sensor and utilized to figure out the motion acceleration. The gravity accelerations are extracted by eliminating the motion accelerations from the accelerometer outputs. Finally, posture estimation is implemented by using a tailor-designed Kalman-based data fusion of the gyroscope outputs and the extracted gravity accelerations. The flow-MIMU device with wireless communication is designed like a watch to be wearable. Experimental results validate that the motion velocity, acceleration and posture of human limb are determined accurately and free of accumulative error in monitoring of dynamic motions using the proposed method. The wearable flow-MIMU device provides an advantageous monitoring approach for applications of personalized rehabilitation, sports training, intelligent prosthetics, etc.