In a method for manufacturing a ridge-type waveguide, a substrate is provided. An etching resistance stripe is coated on the substrate. The substrate with the etching resistance stripe is subjected to a wet etching process to form a ridge under the etching resistance stripe. The etching resistance stripe is removed. A titanium stripe is then coated onto the ridge and diffused into the ridge to form a waveguide in the ridge by a high temperature diffusing process.