Abstract: In order to study the elastoplastic properties of Shanghai silty-sand and the determination of the relevant parameters, consolidated-drained triaxial test with Shanghai silty-sand including 4 sets of 20 specimens had been performed. Soil samples were taken at the depth from 5m to 15m below the ground surface located at the northeast district of Shanghai.In this paper the changing law of such parameters, A, a and P is analysed, the expression of plastic work Wp is derived and presented, the relationship between the elastic work We and plastic work Wp and the axial elastic strain εe and plastic strain εp are discussed. The results of computation agreed fairly well with the measurement in laboratory.It is expected that the results will be helpful to create a new method of settlement computation for silty-sand in Shanghai.