In this article, we have proposed a model for a realistic strange star under Tolman VII metric\citep{Tolman1939}. Here the field equations are reduced to a system of three algebraic equations for anisotropic pressure. Mass, central density and surface density of strange star in the low-mass X-ray binary 4U 1820-30 has been matched with the observational data according to our model. Strange materials clearly satisfies the stability condition (i.e. sound velocities < 1) and TOV-equation. Here also surface red shift of the star has been found to be within reasonable limit.