This paper introduces the Simulated Nelder-Mead Algorithm with Random Variables Updating (SNMRVU), a novel approach for solving large-scale global optimization problems by combining simulated annealing with the Nelder-Mead method. The SNMRVU algorithm enhances performance through strategies like variable partitioning and local search intensification, yielding high-quality solutions with reduced computational costs compared to traditional methods. Performance evaluations on 27 benchmark functions demonstrate SNMRVU's promising efficiency and effectiveness against four other algorithms.