The invention discloses a combined water treatment device and relates to the field of the water treatment device. The combined water treatment device comprises a water pump, a shell, a hanging rack, awater feeding pipeline and a water draining pipeline, wherein a water inlet and a water outlet which are connected with the interior of the shell are formed on the shell; the water outlet of the shell is connected with the water pump; the water inlet of the shell is connected with the water feeding pipeline; a sensor component, a filtering device and a heating device which are connected with eachother are arranged in the shell from the water inlet to the water outlet in turn; the water draining pipeline is connected with the other end of the water pump; the hanging rack is fixed on one sideof the shell; a display component is arranged on the hanging rack; the display component comprises a display arranged on the exterior and a processor arranged on the interior; an output end of the sensor component is electrically connected with an input end of the display component; the output end of the display component is electrically connected with the input end of the heating device. The combined water treatment device is capable of helping the cultivator to observe water, quickly find the factor influencing the health of the aquarium fish and guarantee the health of the aquarium fish.