We present results of calculations of the liquid structure factorS(q)of the alkali metals by using an analytical form for the direct correlation function of the OCP reference system as well as the random phase approximation to consider the electronic screening. The treatment, which is based on the Baus and Hansen model, works well with two parameters γ and x0. It is found out that the valuex20= 2.34 is good to describe the low-q region ofS(q)but unable to reproduce the first peak whilex20= 3.2 makes the situation reversed.