The invention discloses a yarn sizing machine capable of uniformly conducting sizing. The yarn sizing machine comprises a yarn putting device, a cleaning device shell is arranged at the right of the yarn putting device, a driving bin is arranged inside the cleaning device shell, a driving motor is installed inside the driving bin, the front end of the driving motor is connected with a dust tightening device through a gear, a static electricity dust remover is installed inside the cleaning device shell, a size tank is arranged at the right of the cleaning device shell, a first yarn guide rolleris arranged inside the size tank, a yarn extruding roller is arranged at the right of the first yarn guide roller, a sizing roller is installed at the right of the yarn extruding roller, and a secondyarn guide roller is arranged at the upper right portion of the sizing roller. According to the yarn sizing machine capable of uniformly conducting sizing, design of the dust tightening device, the gear, the static electricity dust remover, the yarn extruding roller, an air draft device and an air suction device is adopted, the speed for yarn to absorb sizing agent can be increased, and thereforethe work efficiency of the sizing machine is improved so that the yarn can be more fully dried.