Nowadays, Wi-Fi is closely related to our life as we use Wi-Fi to communicate everyday. At the same time, people are constantly exploring other uses of Wi-Fi. With the release of Channel State Information (CSI) measurement tool, we can achieve more accurate indoor activity and object detection. In order to make a better used of the combination of Wi-Fi sensing tools and data analytic methods, we first have a deep look at CSI and methods of signal processing. Then, we use CSI and SVM, KNN, Decision Tree, LSTM and Random Forest to perform gesture recognition and object detection.