To facilitate the translation of cancer fluorescence imaging into clinical practice, the development of stable and highly specific and sensitive targeted fluorescence probes with low toxicity is desirable. GX1, a gastric tumor angiogenesis marker candidate, holds promise in the target-specific delivery of molecular imaging probes for early gastric cancer detection in vivo. In this study, we describe the design and synthesis of a series of novel penta-methine cyanine dyes using the symmetric synthesis method and further conjugated the dyes with GX1, allowing specific binding to the vasculature of gastric cancer. This efficient synthetic route can decrease the undesired byproducts, while increasing yield. Furthermore, in vivo fluorescence imaging revealed that this novel targeted probe accumulates selectively in the tumor site of SGC-7901 subcutaneous xenograft models. The combination of such novel vasculature-targeted molecular probes with fluorescence imaging technology may improve early detection, metastasis detection, and antitumor angiogenesis therapy for gastric cancer.