Recently, multiple cameras can be calibrated with high precision calibration object. However, most existing methods are often difficult to design and further cause high computational cost. Therefore in this paper, we propose a new method to simultaneously calibrate multiple cameras into a network using free fall motion. Specifically, it first estimates the feature points based on synchronization or asynchronous free fall motion. The extracted feature points are then used as corresponding points for multi-camera calibration. After adding an uncalibrated node into a network of calibrated cameras, our method can fully automatic calibrate multiple cameras using several free fall motion. Finally, the proposed method is evaluated using synthetic data.