Abstract: The matrix of scattering time of flight (MSTF) was proposed to line synthetic aperture array imaging of ultrasonic shear horizontal guided discuss the influence of weld scattering on (SH) waves in plate, which could be used into explicating the relation between the weld scattering and the array imaging of ultrasonic guided waves. The weld scattering factor (WSF) and the MSTF have been used into describing the weld scattering, the cone characteristic of line array signals and the ultrasonic SH guided waves imaging theory of line synthetic aperture array with MSTF were all researched. After that, with the help of the array signals and the array imaging theory, the roles of the WSF and MSTF in array imaging of ultrasonic SH guided waves were emphasized. The result shows that, the weld scattering may cause "multi-peaks" of array signals for the same defects, then the WSF become larger synchronously. Because of which, the rank of MSTF would become larger by multiple times of WSF that lead to pseudo strip-shaped shadows with the same degree, and the characteristic of elliptical cluster tracks of array image become more complicated, especially the background noise of image may increase 50% and signal-nose ratio may decrease 10%. The imaging experiment verify the validity of the theory analyze proposed, and which indicate that the MSTF may be a forceful analysis tool that may be used into researching the influence of weld scattering on line synthetic aperture array imaging of ultrasonic SH waves in plate, which could provide support for array image processing and array image recognition of ultrasonic guided waves in plates with welded structure.