Micro-channels were the main microstructures in most micro-fluidic devices. In this paper, the effects of injection molding process parameters on the replicability of micro-channels profile are studied. Orthogonal experiments (Taguchi method) are carried out to establish the relationship between injection process parameters and replication accuracy for various micro-channels. Experimental results show that mold temperature and packing pressure are the principal factors in molding process. The replication accuracy depends strongly on the processing conditions. The replication accuracy reached about 99.84% using the optimum parameters.