The invention relates to a liquid crystal tuned high power external cavity laser. A light exit is machined in each of the left side wall and the right side wall of a box body, a light amplification chip is arranged at the middle part of the bottom of the box body, a second collimating mirror is arranged at the left side of the light amplification chip, a first collimating mirror is arranged at the right side of the light amplification chip, a mode selection device is arranged at the left side of the second collimating mirror, a multiwave liquid crystal variable retarder is arranged at the left side of the mode selection device, a focusing lens is arranged at the left side of the multiwave liquid crystal variable retarder, a completely reflecting mirror is arranged at the left side of the focusing lens, a convex cylindrical lens is arranged at the right side of the first collimating mirror, a concave cylindrical lens is arranged at the right side of the convex cylindrical lens, and a top cover is arranged at the top of the box body. The liquid crystal tuned high power external cavity laser provided by the invention adopts the liquid crystal variable retarder for tuning cavity length of a laser, so that no moving part exists in the laser, and stability and reliability of the laser are improved; meanwhile, a 'cat eye' structure is formed by virtue of the focusing lens, so that light reflected by the light reflecting mirror returns back, shock resistance of the laser is improved, and the laser provided by the invention can be popularized and applied in the technical fields of atom cooling, remote optical information transmission and the like.