Abstract: By using emodin,rhein,chrysophanol and quercetin respectively,the authors conducted an experiment on the spore output,hyphal viability and vigor,colony forming sporangia and spore germination of the phytopathogens including Alternaria tenuis,Pestalotia sp, Coryneum kunzei and Uromyces dianthi.The result showed that the natural products of anthraquinones as such had notable repression effects on the phytopathogens.Therefore,this discovery not only contributes to studies on physiological and biological metabolism of fungi,but provides good theoretical bases for the development of effective pesticides with the characteristics of low toxicity,no pollution and wide application.