Agricultural science and technology plays a key role in the construc tion of modern agriculture. The connotations and main characters of modern agric ulture in the 21^st century were introduced in this paper. The author broug ht forward that the agricultural science and technology innovation was one of the stro ngest supporters to the agricultural development. It is necessary for the agricu ltural development and for the service of “San Nong” that the agricultural sci ence and technology system should be reformed.