Abstract: Neotyphodium endophytes may improve host grass competitive abilities by increasing seed germination success and enhancing host plant growth under water stress, salt and other environmental stress conditions. To find if there were differences in germination between Neotyphodium endophyte infected (E+) and uninfected (E-) plants of three grass species (Achnatherum inebrians, Festuca sinensis and Hordeum brevisubulatum), eight pH levels (pH 4-11) were used. The results indicated that the germination energy of E+ A. inebrians seed were much higher than those of E- seed at pH 6-11 (P<0.05); the germination rate was significantly higher at pH 4-5; the shoot and radical growth of E+ were higher than those of E-, especially at pH 7-11 (P<0.05); and there was much higher dry weight at pH 4-7. The percentage of abnormal germination of E+ seed at pH 4 and at pH 11 was significantly (P<0.05) lower than that of E- seed. Similarly, E+ F. sinensis seed performed much better than E- seed in germination rate, germination energy, radical growth, shoot growth and dry weight. There were significant differences in germination energy at pH 6-10 (P<0.05), germination rate at pH 4 and pH 8-11 (P<0.05), shoot growth at pH 4-11 (P<0.05), radical growth at pH 10 (P<0.05), and the dry weight of E+ seedlings was significantly greater at pH 4-6 (P<0.05). The percentage of abnormal germination was highest at pH 11 (P<0.05). Compared with E- H. brevisubulatum, E+ seed had greater germination energy at pH 4-11 (P<0.05); the shoot and radical growth were significantly greater than those of E- seedlings at pH 9-11 and pH 8-11 (P<0.05) as was the dry weight at pH 4-11 (P<0.05). The percentage of abnormal germination of E+ seed was significantly less than that of E- seed at pH 4. Overall, the optimal pH value for A. inebrians was 6-9; for F. sinensis was 6-7, and for H. brevisubulatum was 7-9.