A novel near-infrared all-fiber mode monitor based on a mini-two-path Mach-Zehnder interferometer (MTP-MZI) is proposed. The MTP-MZI mode monitor is created by fusing a section of no-core fiber (NCF) and a single-mode fiber (SMF) together with an optical fiber fusion splicer, establishing two distinct centimeter-level optical transmission paths. Since the high-order modes in NCF transmit near-infrared light more sensitively to curvature-induced energy leakage than the fundamental mode in SMF, the near-infrared high-order mode light leaks out of NCF when the curvature changes, causing the MTP-MZI transmission spectrum to change. By analyzing the relationship between the curvature, transmission spectrum, and spatial frequency spectrum, the modes involved in the interference can be analyzed, thereby revealing the mode transmission characteristics of near-infrared light in optical fibers. In the verification experiments, higher-order modes were excited by inserting a novel hollow-core fiber (HCF) into the MTP-MZI. When the curvature of the MTP-MZI changes, the near-infrared light high-order mode introduced into the device leaks out, causing the transmission spectrum to return to its original state before bending and before the HCF was spliced. The experimental verification shows that the MTP-MZI can be used as an all-fiber mode monitoring device to monitor the modes introduced into the optical fiber from the outside, providing experimental and theoretical basis for near-infrared all-fiber mode monitoring in optical information systems.