The invention relates to a device for quickly switching fluids. The device comprises a box body and a partition wall. The box body is provided with a fluid inlet, a first fluid outlet and a second fluid outlet. The partition wall is arranged in the box body and divides the space inside the box body into a fluid inflow region and a fluid outflow region. The fluid inlet is communicated with the fluid inflow region, and the first fluid outlet and the second fluid outlet are communicated with the fluid outflow region. A first hole and a second hole which are used for communicating the fluid inflow region with the fluid outflow region are formed in the partition wall, the first hole is communicated with the first fluid outlet, and the second hole is communicated with the second fluid outlet. A two-hole device for alternately opening and closing the first hole or the second hole is arranged on the partition wall. By the adoption of a box body integrated structure, the device for quickly switching fluids is small in occupied space, economical in investment, simple in structure, safe and reliable, the device can be quickly opened and closed, and generally, the fluids can be switched within the range from 10 seconds to 25 seconds according to the diameter of a pipeline.