The invention discloses an OD passenger flow data-based bypass bus route straightening optimization method, which comprises the following steps of step 1, summarizing effective bus route and station information of a target city, and storing the effective bus route and station information in a route table T; step 2, acquiring passenger flow data and OD passenger flow data of each line in the line table T; step 3, screening out adjustable lines, and determining a bypassing section; step 4, judging whether the bypassing section can be subjected to line adjustment or not according to the passengerflow volume of the bypassing section; and step 5, judging whether the bypassing section has a straightened and optimized path based on the existing road network. According to the method, for the optimization adjustment of refining the line with the overlarge nonlinear coefficient to the line detouring section, compared with the adjustment of the whole line, the possibility of line optimization isincreased. Meanwhile, objective OD passenger flow data is taken as a basis for route adjustment, so that the loss of passenger flow caused by route adjustment is reduced, and the scientificity and reliability of route adjustment are improved.