The invention discloses a self-mixing interference orthogonal detection vibration measuring device and method. A single-mode semiconductor laser diode adjustable in constant current source control outputs incidence laser, one part of the incidence laser is reflected to a second photoelectric diode, and optical signals are converted into current signals which are detected by a second photoelectricdetection module and fed back to a collecting module; the other part of the incidence laser is irradiated on the surface of a to-be-detected object and is reflected to a first photoelectric diode according to the original path, and the optical signals are converted into the current signals which are detected by a first photoelectric detection module and fed back to the collecting module. Comparedwith a traditional self-mixing measuring device, the self-mixing interference orthogonal detection vibration measuring device has the advantages that the orthogonal self-mixing signals can be acquired, inverse tangent demodulation of the vibration signals is completed, signal demodulation difficulty of the system is reduced, high displacement resolution is achieved, demodulation precision of the vibration signals of the system is improved, and real-time and online measuring can be realized.