Microfluidics is an important technology for applications including those for chemistry/biology! medicine and those as tools for fundamental researches. Some microfluidic devices developed seemed to function as sheer miniaturized copies ofthose macro devices and most ofthem lacked sufficient cares ofthose dominant forces in micro scale, e.g. fluid-solid interactions, or only tried to avoid their influences. In fact, the active utilizes of micro scale significant forces tend naturally to be more suitable to manipulate and control flows in micro channels. In addition, the lack of the sufficient fundamental studies on micro flow phenomena and a robust and cost-effective integrating technology, making various functional devices together into a system of specific application, has been always a bottleneck problem in the development of microfluidics. In this review, we discussed some selected topics, which are of certain basic importance and concern what have been developed or are being undergone in our group. Some phenomena, which are incapable of been explained by classical Navier-Stokes theory, has been discussed and the characteristics of flows in micro systems have been described. Some examples of devices developed by our group were provided to further the discussion.