The invention relates to a device and a method for detecting an opening/closing characteristic of a film micro valve in a microchannel, which belong to the field of microfluid systems. The device comprises an input end electrode, a data acquisition card, a computer, an alternating-current power supply and N output end electrodes; and N detection resistors and N amplifiers form N parallel detection and amplification circuits. The method comprises the following steps of: accessing a detection device into the microfluid system to be detected; determining the micro valve to be detected; connecting the input electrode on a liquid inlet port of the microchannel where the micro valve is placed; connecting the N output end electrodes and N liquid outlet ports of the microchannel respectively; closing the micro valve, and detecting voltages of resistors connected with the N liquid outlet ports simultaneously; obtaining an envelope curve of a voltage signal of the resistor on each microchannel; and determining according to the shape of the voltage envelope curves of the resistors connected with the output ports of all the microchannels controlled by the micro valve, and determining that the micro valve is closed totally if the voltages are zero. By the device and the method, a plurality of micro valves can be detected synchronously, the flow of the fluid cannot be influenced and the cost is low.