CSP is a classic model for concurrency. As an imperative concurrent programming language CSP is considered weakly typed. In this paper we equip CSP with a formal second-order type system. The types of processes and prefixed processes are distinguished and they are treated as generic types that can be instantiated by the subtypes of alphabets. The bounded quantifier are introduced to represent bounded generics. We first describe the syntax of the typed CSP, then proceed to define the type rules of the formal type system. Finally some examples of type derivations are shown.