Abstract: A hydroponics experiment was conducted to study the effect of exogenous Ca²⁺ and GA₃ on cucumber germination inhibited by Peganum harmala alkaloid. The results indicate that Ca²⁺ and GA₃, single or combined application treatments, promote cucumber seed germination treated with P.harmala alkaloid, increase germination rate, germination vigor and index; as well as α-amylase, protease, lipase, isocitratelyase, nicotinamide adenine dinucleotide kinase (NADK) and Ca²⁺—ATPase activities; and GA and CaM content in cucumber seeds; but decrease abscisic acid (ABA) content. The synergistic effects of combined Ca²⁺ and GA3 on increasing GA and decreasing ABA are oberseved compared with Ca²⁺ treatment. It shows that exogenous Ca²⁺ and GA₃ can alleviate P. harmala alkaloid inhibition in cucumber germination.