To improve the abilityof calibrating the nonlinearity error of nanometer interferometer by beatwave F-Pinterferometer, a method of using 633 nm external-cavity diode laser (ECL) as the slavelaser is presented in this paper. Based on an AR-coated 637 nm quantum well laser diode,using a diffraction grating in Littrow mount for wavelength selection and output coupling,a tunable 633 nm ECL is developed.The experiment results show that the linewidth isnarrower than 5MHz. A course tuning range of 4 nm around 633 nm is achieved throughtemperature control and grating rotation.By controlling the frequency-tuning device, acontinuous tuning range of 1.8 GHz, which is equivalent to a measurement range of 0.75λ of beatwave F-P interferometer,is realized.