There are two types of Relative Clause(RC) in Archaic Chinese, namely `SUO` RC and `ZHE` RC. They are different in word order and function. `SUO` RC is [S+SUO+V]; `ZHE` RC is [V+ZHE]. `SUO` relativizes the direct object, the indirect object and the oblique object of RC; `ZHE` relativizes the subject of RC. The relativized constituents of these two RCs are complimentary distribution in Accessibility Hierarchy. These two RCs are common in that they are free RCs, which don`t have head nouns. I analyse the grammaticalization paths of relativizer `SUO` and `ZHE`. The relativizer function of `SUO` comes from locative noun `SUO`; the relativizer function of `ZHE` comes from adjective `ZHE` which indicates nonspecific plural. The relativizer function of `ZHE` is completed earlier than that of `SUO`. `ZHE` is more grammaticalized than `SUO`, in that `ZHE` also has the functions of particle. It results in `SUO~ZHE` RC, which has the same function of `SUO` RC, and `ZHE` loses its relativizer function in this RC.