The invention relates to a device for observing coriolis force and an observation method. The device comprises a basin, a tray, a tray holder, a support frame, a water spray pipe, a water outlet pipe, a water return pipe, a pipe joint, a sleeve, a shaft sleeve, a spindle, fillers, a sealing ring, an upper filler pressure cover, a lower filler pressure cover, a water pump, a motor, a large belt pulley, a small belt pulley, a panel, a water pipe, a rotary reducer, a capacitor, a reactor, a transfer switch and the like. The observation method comprises the following steps of: making a basin midline and a rotational center mark, connecting a power supply of the water pump to pump water, and observing the track phenomenon of a water line formed by the water sprayed through a water spray hole; connecting a power supply of the motor to enable the basin to rotate, selecting a rotational speed, a clockwise rotational direction and an anticlockwise rotational direction, and observing the track deflection phenomenon of the water line in a rotating reference system; and when the basin has much stored water, disconnecting the power supply, and draining the water back to a water tank. The method is intuitive in observation and can be used for knowing and researching the coriolis effect and the coriolis force through the track deflection phenomenon of the water line in the rotating referencesystem.