KRAS-G12D mutations are common drivers of pancreatic and colorectal cancers, yet effective targeted therapies remain limited. This study describes the design, synthesis, and biological evaluation of two novel KRAS-G12D inhibitors, GD-2 and GD-4. Both compounds exhibited strong antiproliferative activity in AGS and ASPC1 cancer cell lines, with IC₅。 values ranging from 0.2 to 1.8 µM. The protein binding assay also demonstrated high affinity for KRAS-G12D, with dissociation constants (Kd) of 146 nM for GD-2 and 3.18 nM for GD-4. Mechanistic investigations revealed that both compounds significantly reduced downstream, as evidenced by a clear decrease in phospho-ERK expression. Additionally, molecular dynamics simulations confirmed stable binding interactions within the KRAS-G12D pocket. Collectively, these findings identify GD-2 and GD-4 as promising therapeutic candidates for KRAS-G12D-driven cancers.