The fast online classification (FOC) of network traffic plays a critical role in the network resource management and quality of service support. However, traditional network flow features result in poor performance in FOC (with fewer packets). To tackle the issue, this study proposes two new features: (1) The conditional frequency of packet size (PSize), for which the PSize is quantized into several equal bins and the PSize-level conditional frequency of two consecutive packets is calculated; (2) The statistical feature of rate sequence that is obtained by dividing the inter-arrival time into the PSize sequences. Due to the real-time requirement of online classification, we analyze the time complexity of flow feature calculation and attempt to balance the classification speed and the accuracy in feature selection by reducing the feature dimensionality. In addition, a new feature-embedded hierarchical classification structure is developed for the scenario in which the network video traffic accounts for a relatively large proportion. Fewer packets are used in the early stage of binary classification of non-video vs. video, and then, the subsequent data packets are employed for the fine-grained classification of their respective flows. The effectiveness of the proposed method is evaluated on two real-world network datasets, and our method is compared with the state-of-the-art methods in terms of time performance, resource usage, and classification accuracy. The experimental results confirm the superiority of our approach in fast online classification.