Abstract: Achnatherum inebrians is an intoxicating grass found in the native grasslands of Northwest China. It forms a symbiotic relationship with Epichloё endophyte which can promote plant growth and improve abiotic and biotic stress resistance. In the present study, endophyte-infected (E⁺) and endophyte-free (E^-) seedlings of A. inebrians were grown at 5 ℃ for one month and exposed to exogenous salicylic acid (SA) and abscisic acid (ABA); the physiological response of seedlings was assessed. The results showed that, comparing with the control, ABA and SA treatments increased the total chlorophyll content, proline acid content, soluble sugar content, superoxide dismutase activity and peroxidase activity but decreased malondialdehyde content. After 4 days of growth under SA stress, Epichloё significantly (P<0.05) increased proline content and superoxide dismutase activity, by 51.8% and 62.1%, respectively. After 6 days of SA stress, the chlorophyll content, malondialdehyde content, soluble sugar content and peroxidase activity were significantly (P<0.05) improved in E⁺ seedlings (23.0%, 25.4%, 23.7% and 18.0% higher than those of E^- seedlings, respectively). Epichloё significantly (P<0.05) increased the chlorophyll content, proline acid content, soluble sugar content, superoxide dismutase activity and peroxidase activity under ABA treatment but significantly (P<0.05) reduced malondialdehyde content after 6 and 8 days of stress; the malondialdehyde content of E⁺ seedlings treated with ABA⁺ were 21.1% and 34.3% lower respectively than E^- seedlings treated with ABA^-. In conclusion, the interactions between ABA and SA and Epichloё endophytes alleviated the damage of low temperature stress on A. inebrians seedlings.