The effects of different diluted olive mill wastewater(OMWS) on the germinability and related enzyme activities of wheat and maize seeds were investigated.The germination rate,root length,and related biochemical parameters were tested using the methods of counting,weigh,and colorimetry,respectively.The results showed that the influence on the germination rate,germination vigor,and growth was based on the concentrations of OMWS.The OMWS with low dilution ratio(Original and D5) treatments were not only inhibited the seeds germination,but also delayed the growth of leafbud and root,even had more phytotoxicity.The inhibition reduced with the decreasing of OMWS concentration.However,higher dilution ratio groups(D30 and D50) promoted the seed growth behavior.The effects of OMWS on the changes in soluble protein content,catalase(CAT),peroxidase(POD),and phenylanlanine ammonia lyase(PAL) activities also displayed the tendency of inhibition under high,and induction under low concentration.There was significant positive correlation between root length and POD and PAL activities.It was concluded from the results that the influence of OMWS on the germination and growth of wheat and maize seeds had dual effects with inhibition and induction according to the dilution of OMWS.The most important effect was possibly attributed to the contents of phenolic compounds in OMWS.In view of the phytotoxicity caused by phenolics and oxidation products,we suggest to do a dilution pretreatment when OMWS used as organic fertilizer or soil conditioner.