Network intrusion detection is the fundamental of the Cybersecurity which plays an important role in preventing the systems away from malicious network traffic. Recent Artificial Intelligence (AI) based intrusion detection systems provide simple and accurate intrusion detection compared with the conventional intrusion detection schemes, however, the detection performance may not be reliable because the models in the AI algorithms must output a prediction result for each incoming instance even when the models are not confident. To tackle the issue, we propose to adopt Bayesian Deep Learning, specifically, Bayesian Convolutional Neural Network, to build intrusion detection models. Moreover, an ensemble-based detection scheme is further proposed to enhance the detection performance. Two open datasets (i.e., NSL-KDD and UNSW-NB15) are used to evaluate the proposed schemes. In comparison, Convolutional Neural Network and Support Vector Machine are implemented as baseline IDS (i.e., CNN-IDS and SVM-IDS). The evaluation results demonstrate that the proposed BCNN-IDS can significantly boost the detection accuracy and reduce the false alarm rate by adopting the proposed T-ensemble detection scheme.