Theoretical and interpretative study on the subject of photodetachment of H- near a partially reflecting surface is presented,and the absorption effect of the surface is investigated on the total and differential cross sections using a theoretical imaging method.To understand the absorption effect,a reflection parameter K is introduced as a multiplicative factor to the outgoing detached-electron wave of H- propagating towards the wall.The reflection parameter measures.how much electron wave would reflect from the surface;K=0 corresponds to no reflection and K=1 corresponds to the total reflection.