We will describe the PECAT (Pilot English-Chinese Computer-Aided Translation) tool based on a parallel corpus. There are three modules in the system: corpus-processing, matching and post-editing. In order to increase the robustness of the alignment, we use both a length-based algorithm and a bilingual lexicon. The matching algorithm of an input sentence and source sentence is a three-layer Edit Distance algorithm guided by the user, which includes information of word morphology and word POS. Post-editing is a kind of sentence completion under development. Preliminary experiment results are showed with some suggestions for further work.