Using the oil tree peony ‘Fengdan’ as the material, the whole plant was sprayed with four concentrations(50, 100, 200, 400 μmol/L) of methyl jasmonate(MeJA), with spraying clear water treatment as the control(CK). After continuous spraying for 3 d, the plants were subjected to drought stress and then re-watered, and ‘Fengdan’ samples were taken respectively after 2 d of moderate drought, 2 d of severe drought and 2 d of re-hydration. The content of osmotic regulators, malondialdehyde(MDA), photosynthetic pigment content, and photosynthetic indicators in ‘Fengdan’ leaves were measured. The results showed that after induction treatment with 200 μmol/L MeJA, the proline content of ‘Fengdan’ seedlings with moderate drought was the highest, which was significantly increased by 250.34% compared with CK; the net photosynthetic rate, stomatal conductance and transpiration rate of ‘Fengdan’ seedlings with moderate drought were the highest, which were respectively 25.73%, 68.0% and 43.04% higher than those in CK; the contents of chlorophyll a, chlorophyll b and carotenoid reached the highest under 400 μmol/L MeJA treatment, which were increased by 33.33%, 26.09% and 34.48% respectively compared with CK. For the ‘Fengdan’ seedlings with 200 μmol/L MeJA and suffered severe drought, the soluble sugar content reached the maximum, the net photosynthetic rate increased by 41.73% compared with CK. The transpiration rate and intercellular CO2 concentration were the highest under 400 μmol/L MeJA treatment, which were respectively 74.07% and 13.44% higher than that with CK. The increase in the content of these indicators alleviated the increase in the content of MDA. After re-hydration, appropriate concentration of MeJA treatment can restore to different degrees the above-mentioned photosynthetic physiological indicators. The results showed that exogenous MeJA treatment could enhance the resistance of ‘Fengdan’ seedlings to drought, increase the photosynthetic rate, photosynthetic pigments and osmotic adjustment substances contents of ‘Fengdan’ seedlings, and reduce the damage to cell membrane caused by drought. Treatment with 200 μmol/L MeJA showed the best alleviation effect.