The invention relates to a bidirectional term aligning method and device. The method comprises the steps of constructing a first term aligning model from the source language to the target language and a second term aligning model from the target language to the source language; fusing the term aligning models in the two directions with a consistency evaluation function, and constructing an initial target function; conducting joint training on the term aligning models in the two directions with the consistency evaluation function, so that an optimized target function is formed; conducting term alignment on parallel double sentences with the model obtained through the optimized target function and joint training, so that a bidirectional term aligning result is obtained. A system comprises an aligning model constructing module, a target function constructing module, a joint training module and a term aligning and analyzing module. By means of the method and device, due to the fact that the consistency evaluation function is introduced, joint training can be conducted on the term aligning models in the two directions, so that the term aligning models in the two directions conduct error correction for each other, and the error rate of term aligning is greatly lowered.