Sarcasm is a form of figurative language where the literal meaning of words cannot hold, and instead the opposite interpretation is intended in a text. Sarcasm detection is a significant task to mine fine-grained information, which is a much more difficult challenge for sentiment analysis. Both industry and academia have realized the importance of sarcasm detection. However, most existing methods do not work very well. Using a neural architecture, we propose a novel multi-dimension question answering (MQA) network in order to detect sarcasm. MQA not only introduces the abundant semantic information to understand the ambiguity of sarcasm by multi-dimension representations, but also builds the conversation context information by deep memory question answering network based on bidirectional LSTM and attention mechanism to discover sarcasm. The experimental results show that our model has ability to obviously outperform other state-of-the-art methods, and then further examples also verifies the advancement and effectiveness of our proposed network for detecting sarcasm.