Abstract: Bi-directional Blowers capable of sucking-in ambient air and blowing-out hot air from system box simultaneously are invented to cool computer or electronic systems. The application to cooling laptop computers is disclosed in very details. The bi-directional blowers are comprised of a DC or AC motor, a rotary part of blades and/or impellers, an optional cover, and a housing frame with built-in broken walls, stationary blades and airfoils, which control the flow volume and direction. The separate zone to divide the blow-out and suck-in channels is constructed using the broken walls with conjunction of the blades and/or impellers. The rotary part is the radial blades, or a combination of blades and impellers. Two types of bi-directional blowers are explored: the pressure type and hybrid type. A one-way blower of pressure type utilizes the same principle of the bi-directional blowers such that the inlet and outlet can be located on sides of the blower.