A handwriting detecting system based on micro-accelerometers and micro-gyros is proposed,and the algorithm of the detecting system is also described in detail. The micro-accelerometers and micro-gyros mounted on the pen are used in this dynamic handwriting acquisition system to acquire the dynamic information,and obtained data are transmitted to computer for data processing and feature analysis through a serial port after A/D conversion.The motion track of the pen in the 3-D space can be recognized through computing the matrix of attitude angles and the dynamic information of the pen is mapped on the 2-D plane. Then,the information of handwriting can be recurred on the writing plane by an integral. Finally,this paper introduces the influence of gravity acceleration on the handwriting recurrence in the movement of the pen,gives a solution to get pure movement acceleration from the gravity acceleration detected by the micro-accelerometer,and describes the sensor calibration method. Experimental results prove the designed system to be feasible.