We present a microfiltration chip that extracts blood plasma with pulsatile pressures and without using any external equipment. The chip generates pulsatile pressures to significantly reduce filter clogging, and consists of oscillator, plasma-extraction pump, and filter units. The oscillator autonomously converts constant water-head pressure to pulsatile pressure, and the pump uses the pulsatile pressure to extract plasma through the filter. Because the pulsatile pressure can periodically push cells in the blood against the filter surface, filter clogging can be effectively reduced. In this way, we show that plasma volume extracted with the pulsatile pressure is about ten times higher than that with the constant pressure.