In this paper, a series of s-triazine derivatives were synthesized for the application of second-order nonlinear optical materials. Their first hyperpolarizabilities (β) were estimated with solvatochromic method. From the results, it can be inferred that the first hyperpolarizabilities of s-triazine derivatives are highly dependent on the molecular structures. Furthermore, the relationship between molecular hyperpolarizability and structure was elucidated based on the theoretical calculation of molecular orbitals.