A test of the uniaxial compressive stress-strain curve under different strain rates was carried out on seawater and sea sand recycled aggregate concrete（SSRAC） considering different ages and shell contents. The results show that the 600 d peak stress and peak strain of SSRAC increase by 10.4% and 23.2%， respectively， as compared with those of natural aggregate concrete（NAC）. However， the elastic modulus of SSRAC decreases by 29.1%. The strain rate sensitivity of SSRAC increases with the increase in shell content. Then， based on the model in GB50010， a dynamic constitutive model is proposed for SSRAC under medium and low strain rates （from 10^-5 s^-1 to 10^-1 s^-1） considering the dynamic increase factor of characteristic parameters. Finally， mechanism analyses of the characteristic of its stress-strain curves are given.