Abstract: In this paper, how biological potassium fertilizers have been sought for and used in recent years has been summarized; the character of supplying potassium by incorporating rice straws into paddy fields as well as its application method and efficiency has been analyzed; the ability to enrich potassium and characters of Alternanthera philoxeroides(Mart.), Pistia stratiotes L. and Azolla as well as the effect of biological potassium fertilizer on the growth of rice have been discussed; comparisons have been made of different application methods of different biological fertilizers and their different benefits; views and suggestions as to the development and use of biological potassium fertilizers have been given; and the potential and possible ways of seeking for potassium-rich plants have also been dealt with.