In this paper, positive and unsaturated linear magnetoresistance (LMR) in an LaAlO3/SrTiO3 two-dimensional electron gas system is reported. LMR appears in this system over a wide range of temperatures and magnetic fields and does not tend to saturate at magnetic field up to 14 T. The spatial fluctuation in mobility is the most likely origin of positive unsaturated LMR because the existence of strong Shubnikov-de Haas oscillations rules out the extreme quantum origin. Moreover, LMR ∝ μ and HC ∝ 1/ μ are confirmed and meet the requirements of Δ μ/ μ < 1 in the classical model proposed by Parish and Littlewood. This suggests that the observed LMR is the classical LMR effect induced by a narrow mobility distribution. These findings are of great interest for the practical application of magnetoresistive devices such as magnetic sensors, magnetometers, and magnetic storage devices.