The invention discloses a method for activating black and odorous river course raw water by bypassing new water. The method comprises the following steps: introducing black and odorous river course raw water into an absorbing well; filtering off big-volume impurities through a grid, and then introducing into a collecting well; sucking the water in the collecting well into the initial end of an ABR reactor, guiding by a guide plate in the ABR reactor, and performing denitrification nitrogen removal and anaerobic phosphorus release reaction on sludge beds in various reaction chambers; introducing the effluent water after treatment by the ABR reactor into an MABR membrane bioreactor, and performing aerobic phosphorus accumulation reaction and nitration reaction; returning the effluent water at the tail end of the MABR reactor into the ABR reactor, and further performing denitrification nitrogen removal and anaerobic phosphorus release reaction; introducing the water body after further treatment by the ABR reactor into the MABR reactor, and further performing aerobic phosphorus accumulation reaction and nitration reaction; introducing the effluent water from the MABR reactor into a discharge bay; and introducing the water in the discharge bay and the black and odorous river course raw water into a mixing treatment device, mixing, and discharging the mixed effluent water to the original river course.