The utility model discloses a holder and a holder-based acidizing etching instrument. The holder comprises a visual core holder which is of a hollow closed structure. The upper end of the visual core holder is provided with an upper end through hole; the lower end of the visual core holder is provided with a lower end through hole; and the upper end through hole and the lower end through hole are both communicated with the interior of the visual core holder. According to the holder-based acidizing etching instrument, one inch of cylindrical core is adopted and is easy to process, and moreover, experimental study can be performed by adopting a reservoir actual core; the core etched form can be tracked in real time. Moreover, the whole process of an acid-rock reaction is reflected truly, and meanwhile, the research on the change of annular break flow conductivity can be performed to achieve the goals of optimizing an acid liquor system and an acidizing process.