Abstract: The effects of four potassium fertilizer rates with additional foliar application on fresh pod marketable yield and seed number at maturity in vegetable soybean were investigated under normal N and P fertilizers by pot experiment.Though responses were different between cultivars,potassium application at seeding significantly increases the marketable yield and seed number at maturity.Maximum yield components are all obtained at 120 kg·hm^-2 K rate except standard pod number per plant in CAS Edamame No.1.Compared with control,the fresh pod weight,fresh seed weight,and seed number per plant of CAS Edamame No.1 at 120 kg·hm^-2 K rate,are increased by 31.5%,16.2% and 34.0% respectively;while line No.121 are increased by 34.2%,50.5%,and 32.4% respectively.At 120 kg·hm^-2 K rate,additional foliar application of potassium at flowering and pod-setting stages increases the fresh pod weight,fresh seed weight,and seed number per plant by 8.8%,48.5% and 5.8% in CAS Edamame No.1,and by 3.5%,28.0% and 3.6% in line No.121 respectively.K application has no effect on standard pod number but significantly increases seed number and seed weight.Maximum marketable yield could be realized at 120 kg·hm^-2 K₂SO₄ with additional foliar application of 30 kg·hm^-2 of K₂SO₄.