Dysphagia is a common complication of strokes, and the patients usually have clinical problems such as malnutrition, significant weight loss, and aspiration pneumonia. Measuring the muscle activity pattern to describe physiology of swallowing behavior by surface electromyography (sEMG) is a simple, non-radioactive, and non-invasive method. Most of previous studies described the swallowing behavior by the terms of amplitude and duration. However, there is no objective and precise approach to evaluate swallowing coordination. For more precisely evaluate swallowing coordination of dysphagia, a wireless and wearable monitoring device was designed to measure four muscle groups simultaneously under swallowing. In this study, the algorithm of bilateral muscle pattern detecting was also developed to extract and analysis the difference swallowing feature of sEMG patterns. The experimental result shows that the amplitude and latency variation for dysphagic patients are significantly larger than those for healthy subjects under different swallowing conditions.