This paper first establishes a structural equation model to reflect the relationship between latent variables and analyzes the influence of parents' psychological capital on children's social skills in four dimensions. The partial least squares regression is applied to the component data, and a new modified weighted symbol weight sum is proposed to obtain the estimated value of the latent variable and the modified weighted symbol weight sum makes the model fit better. The results show that the average values in urban areas are 3.77, 3.60, 3.20 and 4.15, all higher than those in rural areas. It shows regional differences in the influence of parents' psychological capital on children's social skills, and urban children have the strongest social interaction abilities.