The invention relates to a method for preparing a colored light-extinction polyester filament. The method comprises the following steps of: firstly smashing a polyester chip after being subjected to pre-crystallization into powder and mixing the power with pigment and a light-extinction agent to obtain a mixture, and then drying the mixture and adding a dispersing agent after solid phase polymerization, and melting and extruding to obtain a polyester master batch; and mutually mixing the melted and extruded polyester master batch with a melt of a polyester parent body, then spinning and shaping to obtain a tow, and air blast cooling and shaping to obtain the polyester filament after oiling through an oil tanker, drawing and winding. According to the invention, solid phase polymerization on polyester is carried out in the preparation process of the master batch so that the excessive degradation of the polyester is avoided, the viscosity of the polyester is increased, the subsequent spinning operation is easy and the product quality of filament is improved; ethers, polyhydric alcohol or ester compounds serving as dispersing agents are added in the master batch preparation process sothat the pigment and the light-extinction agent are easily dispersed without condensing, the filament spinnability is greatly improved and the sequence processability of the filament is improved; andthe manufacturing cost is greatly saved.