The invention discloses an automatic water quality detection device, and relates to the field of water quality detection. The automatic water quality detection device comprises a base, a sampling andinjection mechanism, a water sample extraction power mechanism, a test package and a driving mechanism, wherein the sampling and injection mechanism is provided with a water inlet, which is used to obtain water samples; the water sample extraction power mechanism is connected to the water inlet, and provides power for the sampling and injection mechanism to obtain the water samples; the test package is arranged on the base and the sampling and injection mechanism can inject water samples into the test package; and the driving mechanism can drive the sampling and injection mechanism to inject water samples into the test package. In the automatic water quality detection device provided by the invention, the sampling and injection mechanism can automatically obtain water samples through the water sample extraction power mechanism, and the sampling and injection mechanism can inject the obtained water samples into the test package under the drive of the driving mechanism, thereby realizingautomatic sampling and automatic detection. The detection device is simple and convenient to operate, reduces labor costs and improves work efficiency.