Directed immune cell migration plays important roles in immunosurveillance and immune responses. Understanding the mechanisms of immune cell migration is important for the biology of immune cells with high relevance to immune cell trafficking mediated physiological processes and diseases. Immune cell migration can be directed by various guiding cues such as chemical concentration gradients (a process termed chemotaxis) and direct current electric fields (dcEF)(a process termed electrotaxis). Microfluidic devices that consist of small channels with micrometer dimensions have been increasingly developed for cell migration studies. These devices can precisely configure and flexibly manipulate chemical concentration gradients and electric fields, and thus provide powerful quantitative test beds for studying the complex guiding mechanisms for cell migration. In the research of this thesis, a PDMS-based and a glass-based microfluidic devices were developed for producing controlled dcEF and these devices were used to analyze electrotaxis of activated human blood T cells. Using both devices, we have successfully demonstrated that activated human blood T cells migrate toward the cathode of the applied dcEF. Furthermore, a novel microfluidic device was developed to configure better controlled single or co-existing chemical gradients and dcEF to mimic the complex guiding environments in tissues and this device was used to investigate the competition of chemical gradients and dcEF in directing activated human blood T cell migration.