A study was conducted to investigate the effects of different pH(3,5,7,9,11)on variations of growth and ergot alkaloids concentrations in symbiont of Epichlo gansuensisAchnatherum inebrians seedling.The results showed that:1)the plant height,root length and biomass of A.inebrians had peak value under pH 7,and had significant differences (P<0.05) than the other four pH treatments,and the four kinds of growth index under strong alkaline treatment were significantly (P<0.05) higher than that under acid treatment.2)Chlorophyll content had maximum under pH 7,which had significant(P<0.05) differences higher than that of pH=3，5 and pH 11,and under strong alkaline treatment were significantly (P<0.05) more than acid treatment.Soluble sugar under five pH treatments difference was not significant (P>0.05).3)The contents of ergine under pH 9-11 had a peak value at 15 d，which had significant(P<0.05) difference with other treatments.The contents of ergonovine under pH11 had maximum at 15 d，which were significantly(P<0.05) enhanced by increasing pH.To sum up,Symbiotic seedlings grow best under neutral conditions and under alkaline conditions grow well more than that under acidic conditions.However,the accumulation of ergine and ergonovine had peak values under strong alkaline conditions.Comprehensive growth and ergot alkliold production,the symbionts can be used in the cultivation of salinealkali land greening.