The invention discloses a large-scale electric automobile charge and discharge multi-target optimization method based on a sine cosine algorithm (SCA). According to the method, large-scale electric automobiles are grouped and classified by using a similar grouping method, and formulation of an electric automobile group charge and discharge strategy is performed by using the SCA so as to realize the objectives of power grid side peak shaving and minimum user side charge expense. Besides, the adopted sine cosine algorithm is a new intelligent algorithm and has the characteristics of faster rate of convergence and higher global convergence in comparison with the classic genetic algorithm (GA) and particle swarm optimization (PSO) and the like so that formulation of the electric automobile charge and discharge plan is enabled to be more reasonable.