This paper describes a detailed procedure for identifying a microscopic randomness of a particle-reinforced composite material considering a microscopic uncertainty in elastic property of component materials of a particle reinforced composite material. Some reports on the stochastic homogenization analysis considering a microscopic random variation can be found in literatures. A microscopic stress field will take an influence of the microscopic variation, the stochastic microscopic stress analysis will be also important. In the previous reports, it is assumed the microscopic random variation is known. However, it is sometimes difficult to identify a microscopic random variation in a composite material especially after manufacturing process. An identification process for a microscopic randomness with solving an inverse problem, therefore, will be needed for the stochastic microscopic stress analysis. In this paper, an inverse stochastic homogenization problem is tried to be analysed with the inverse homogenization analysis and the Monte-Carlo simulation for the stochastic homogenization analysis. With numerical results, accuracy of the inverse analysis is discussed.