Abstract: To investigate the processing stages of the SNARC effect for letters and the influence of dual coding cues (verbal and visual), this experiment employed uppercase letters as stimuli with reference to alphabetic sequence framework, adopting a letter sequence judgment task to concurrently elicit the SNARC effect for letters, Stroop (semantic representation stage), and Simon (response selection stage) effects. The results revealed that: (1) The SNARC effect for letters demonstrated significant interactions with both the Stroop and Simon effects, indicating that the SNARC effect for letters mediated by ordinal information exists simultaneously during both semantic representation and response selection stages. (2) Ordinal information can robustly induces the SNARC effect for letters through the synergistic coordination of verbal and visual coding cues.