This study investigated the relationship between the knowledge of Applied Contrastive Analysis (CA) and Translation Quality of Translation Trainees. To achieve the purpose of the study, 70 male and female participants took an English proficiency test and 60 of them were selected to take part in the study. Then, they sat for the test of the knowledge of Applied Contrastive Analysis and translation tests. The CA test only contained lexical and grammatical CA points. Regarding the translation quality of translation trainees, a text including three paragraphs was given to them and then the quality of the translated work was measured using Waddington (2001) model. After that, correlational analyses were conducted to determine if there is any meaningful correlation between them or not. Regarding the question of the study, the result showed that, there is a significant relationship between Applied Contrastive Analysis knowledge and translation quality (r = 0.757). Therefore, we can conclude that knowledge of Applied Contrastive Analysis has a positive impact on Persian-English translation of translation trainees.