we report a wavelength-tunable watt-level continuous wave (cw) red laser that uses a composite cavity based on an intracavity sum-frequency generation (sfg). the composite cavity is composed of a ld side-pumped nd: gdvo4 p-polarized 1062.9 nm resonant cavity and a resonant optical parametric oscillator (sro) of s-polarized signal light using a periodically poled crystal mgo:ppln. based on the temperature tuning from 30 degrees c to 200 degrees c, the cw red laser beams are obtained in a tunable waveband from 634.4 nm to 649.1 nm, corresponding to a tunable output waveband from 3278.0 nm to 2940.2 nm of the mid-infrared idler lights. the maximum cw output power of the red laser at 634.4 nm and the idler light at 3278.0 nm reach 3.03 w and 4.13 w under 30 degrees c, respectively.