The hardening strain model with small strain (HSS) can appropriately consider the nonlinear and stress-dependent behavior of soils at small strain range. Thus

it is widely used for deformation predictions during pit and tunnel excavations. However

currently there is a lack of systematic study on how to reasonably and conveniently determine all the model parameters. This paper firstly introduces the definitions of all the HSS model parameters and their measurements. Based on the statistics of laboratory and field test data

the relationships between the model parameters and the void ratio of Shanghai soils are proposed

which can be conveniently used in engineering practice. Finally

the HSS model with parameters determined by the proposed method is used to analyze the deformation in four excavation cases. The results show that with the field measured small strain shear stiffness

the calculated lateral deformations of the retaining wall agree well with the measurements. It indicates that the proposed method for determining the HSS model parameters is appropriate and it can provide references for similar projects in Shanghai and similar regions.