The invention relates to the technical field of wastewater treatment and particularly relates to a system for intelligently controlling dosing amount in heavy metal wastewater treatment. The system includes, in a successively connected manner, a first water quality auto-analysis device, a first flow sensor, a reaction tank, a second water quality auto-analysis device, a first electric valve and asecond flow sensor, and also includes a backflow bypass connected between the second water quality auto-analysis device and the first electric valve. The backflow bypass is successively provided witha second electric valve and a third flow sensor. The system further includes a reagent metering pump connected to the reaction tank, and an intelligent control system respectively connected to the first water quality auto-analysis device, the second water quality auto-analysis device, the flow sensor and the reagent metering pump through signals. During control of dosing amount, the system can change the dose by fluctuation of heavy metal content in the wastewater, so that on the basis of guaranteeing the effluent quality, waste of the reagent is reduced, and quantity of sludge is reduced, misjudgment rate by manual work is reduced, and high efficiency and manpower saving are achieved.