Miniaturization of analytical instrument is one way of addressing the issues of sensitivity, measurement speed, throughput and cost of analysis in biology analysis. Microfluidic devices can be used to manipulate the microscale sample expediently, and have many advantages including minimum sample consumption and minimum cross contaminant, which are typical problems in other conventional standard fluidic devices. The highly integrated microfluidic devices were suitable for high-density, parallel sample processing, and high-throughput analyses with extremely high duty cycles. Besides the optical spectroscopic measurement and electrochemical detection, mass spectrometry has been coupled to microfluidic devices as detector, resulting in rapid analysis of complex biological samples with high throughput and confidence. Microfluidic devices utilizing chromatographic or capillary electrophoresis separation techniques are under fast development, showing a predominant trend in modern analytical science. After giving a brief introduction to background of the microfluidic devices and fabrication techniques, documenting the technologies and applications of microfluidic mass spectrometry for the analysis of biological samples and emphasizing on the emergence of interfaces coupling microfluidic devices to various mass spectrometers for applications in proteomics, metabolomics and other biotechnology areas are reviewed.