This paper optimizes human resource management from the perspective of marginal utility. The utility function proposes the subtraction function of consumption, which represents the law of diminishing marginal utility. The Lagrange multiplier method solves the maximum utility problem. In human resource management, utility and marginal utility are redefined, and the probability density function and distribution function of exponential distribution are used as the index’s marginal utility and utility functions, respectively. Human resource management optimization models I and II were constructed based on the marginal utility, and the models and model parameters were solved. This paper applies the human resource management model to Company R as an example. The calculation shows that the total investment of the current index resources of Company R is 2.55 million yuan, and the total utility calculation is 0.8306. Under the optimization of human resource management based on Model I, the expected value of company R reached 0.8631 while maintaining the unchanged index resource input, an increase of 3.91%. The optimization based on Model II resulted in the index resource input being 2.3285 million yuan, with an unchanged total utility that was reduced by 8.69%.