The invention discloses a data enhancement method applied to neural machine translation. The method comprises the steps that word alignment processing is conducted on bilingual training linguistic data to obtain word alignment information; minimum translation units contained in the bilingual training linguistic data are determined according to the word alignment information; all the minimum translation units are calculated according to a preset vector representation calculation rule, and corresponding vector values are obtained; the similarity value between all the minimum translation units iscalculated through a cosine formula; whether the similarity value exceeds a threshold or not is judged, and if yes, the position of the minimum translation unit, corresponding to the similarity valueexceeding the threshold, in the bilingual training linguistic data is exchanged, and new bilingual training linguistic data is obtained. By means of the method, the new bilingual linguistic data canbe formed, and the training linguistic data can be effectively increased; the structure information of the original linguistic data is enriched, and the improvement of the low-resource language translation quality of neural machine translation is achieved. The invention further discloses a data enhancement system and device and a computer readable storage medium which have the above advantages.