Bacillus thuringiensis is well known as an effective bio-insecticidal bacterium. However, the roles of B. thuringiensis to control plant diseases are not paid great attention to. In recent years, many new functions in protecting plants from pathogen infection have been discovered. For example, acyl homoserine lactone lactonase produced by B. thuringiensis can open the lactone ring of N-acyl homoserine lactone, a signal molecule in the bacterial quorum-sensing system. This in turn, significantly silences bacterial virulence. This finding resulted in the development of a new strategy against plant bacterial diseases by quenching bacterial quorum sensing. Another new discovery about B. thuringiensis function is zwittermicin A, a linear aminopolyol antibiotic with high activity against the Oomycetes and their relatives, as well as some gram-negative bacteria. This paper summarized the relative progresses of B. thuringiensis in plant disease control and its favorable application prospects.