The invention provides a WAMS (wide area measurement system) and SCADA (supervisory control and data acquisition) integrated data based grid forced oscillation source positioning method. Oscillation sources are positioned rapidly and accurately by comprehensive utilization of data of the WAMS and SCADA. According to a main principle, the method includes: firstly, positioning general directions of the oscillation sources by adopting an energy flow function method based on 500kV grid WAMS data, then adopting different accurate oscillation source positioning methods according to properties of three common oscillation sources, computing tie lines of a local weak tie network by adopting an SCADA data based oscillation extreme point judgment method, and judging whether oscillation exists in the weak tie network or not; adopting WAMS data of generator excitation voltage phase to judge whether oscillation is caused by a generator excited system or not; adopting an extreme point computation method of SCADA data of valve or guide vane opening of a generator set to judge whether grid oscillation is caused by a unit prime mover or not.