This study investigates the impact of source-text metaphors on the cognitive patterns when translating in both directions of a language pair and whether this impact is affected by directionality. Thirty-eight Chinese trainee translators performed a series of translation tasks from Chinese to English and from English to Chinese, and their performances were recorded by eye-tracking and keylogging and all participants gave cue-based retrospective reports. Four eye-key combination indicators were calculated using generalized linear models to demonstrate translators’ allocation of cognitive resources: Total Attentional Duration, Attention Unit Count, Attention Unit Duration, and pupil dilation. The eye-key data were compared with the participants’ introspections. The overall findings suggest that translation directionality can significantly affect the relationship between processing types (ST processing, TT processing and parallel processing), metaphor-related text types and attention distribution patterns. Detailed eye-key descriptions show that this impact is inconsistent.