We have presented the method of evaluation of relative effective screening parameters [q_s(q,T)/ g(0,0)] as a function of wave vector q for different temperature for silicon inversion layer Si(001). The evaluation has been done by the theoretical formalism of Egeinluz and Maradudin. The dielectric constant for the physical system in the form of inversion layer has been discussed in a homogeneous medium with dielectric constant k. For small q this dielectric constant leads to the same result. For q>K, the screening effect falls off much more rapidly. This has been taken when the long wavelength dielectric constant at absolute zero is considered for as ideal two-dimensional electron gas of very low density. The present parameter given by eq. (28) is independent of carrier concentration and one with get very unphysical result that at a very low density of carriers continue to screened as effectively as a higher density. The difficulty is removed by eq. (35) because k_r goes to zero as the density goes to zero. This shows that the screening affects a smaller and smaller range of q.