Accurate dosing method and system

The invention provides an accurate dosing method. The accurate dosing method comprises the following steps: measuring the chemical oxygen consumption of to-be-treated water; determining the dosage ofa coagulant based on the measured chemical oxygen consumption of the to-be-treated water; and adding a coagulant into the to-be-treated water according to the determined dosage of the coagulant. Inventor discovery, the chemical oxygen consumption of the to-be-treated water and the dosage of the coagulant have strong correlation; therefore, the dosage of the coagulant can be directly obtained basedon the chemical oxygen consumption of the to-be-treated water, accurate rapid simple coagulant dosing amount determination is realized; according to the method, the relevance between the water quality of the to-be-treated water and the treatment process is given, basis support is provided for guiding production, reasonably using chemicals and guaranteeing the effluent quality and the treatment effect, the water treatment