The invention relates to an excitation angle variable integrated plasma enhanced Raman spectrum detection device, and belongs to the technical field of analytic instruments for chemical detection. The detection device is composed of a laser, a collimating lens, a narrow band filter, an excitation angle variable optical mechanism, a nanoparticle and nano film coupled SERS (Surface Enhanced Raman Scattering) substrate, a long pass filter, a focusing lens, an optical fiber and a Raman spectrometer. Based on the excitation angle variable optical mechanism, an optical collective lens matches with the existing portable Raman spectrometer and the SERS substrate having SERS signal enhancement and directional transmission properties to form the integrated plasma enhanced Raman spectrum detection device. The device can realize continuous change of the excitation angle of incident exciting light to satisfy the excitation requirements of surface plasmas, and can realize effective collection of directionally transmitted SERS signals based on the directional transmission property of the plasmas. The device is convenient to carry and sensitive in detection, thereby being particularly suitable for quick monomolecular-level field analysis.