Abstract: To explore the effects of exogenous betaine solution on secondary metabolites and nitrogen metabolism enzyme activities of Pinellia ternata in a drought environment,a water pot control experiment was used. The treatments were D (drought treatment,35%±2% moisture content),D₂₀ (drought treatment with spray of 20 mmol/L betaine),and D₄₀ (drought treatment with spray of 40 mmol/L betaine). Glutamate synthase (GOGAT),glutamine synthetase (GS),glutamic dehydrogenation enzyme (GDH),nitrate,soluble protein,alkaloids,guanosine and adenosine contents of P. ternata were measured in each treatment group. As drought time increased,the GOGAT and GS activities of D₄₀ decreased slower than those of D,and D₂₀,while GDH activity initially increased but then decreased. However,the CK (control group,75%±2% moisture content) group did not change significantly. The alkaloids in the D₄₀ group improved 6.3% (9 days),10.3% (18 days) and 12.3% (27 days),which was higher than those in the D₂₀. The nitrate,alkaloids and guanosine contents increased with time were higher in the D₄₀ group than in the D₂₀ group,although the CK group was the highest. The adenosine content tended to decrease when the drought stress time reached 27 d. At 27 d,the content of soluble protein in the D₄₀ group was 7.3% higher than in the D,as well as 3.1% higher than in the D₂₀.The 40 mmol/L exogenous betaine solution concentrations increased nitrogen metabolism enzyme activities in P. ternata under drought conditions. This may accelerate the inorganic nitrogen assimilation,which is conducive to the accumulation of secondary metabolites and enhances the ability of P. ternata to resist drought stress.