The invention discloses a microwave photonic broadband phase shifting method. Firstly, the optical carrier is divided into two equal paths. Then, the two optical carriers are phase modulated by two microwave signals which are inverted but have the same other parameters, so as to obtain two optical signals with phase modulation.A pi/2 phase difference is introduced for the two phase modulated optical signals, and the pi/2 phase difference is coupled into one optical signal by an optical coupler with adjustable coupling ratio; a light filter is used to filter one of that first-order sideband ofthe coupled optical signal, and then the first-order sideband is photoelectrically detected to obtain a phase-shifted microwave signal, and the phase of the phase-shifted microwave signal is continuously adjusted in a large range by adjusting the coupling ratio of the optical coupler. The invention also discloses a microwave photonic broadband phase shifting chip. The invention adopts two phase modulators to realize the photon-assisted microwave phase shift, the structure is simpler, the system on-chip integration is easier to be realized, the device volume is reduced, the system stability isimproved, and the manufacturing cost is greatly reduced.