The present invention provides a vertical axis wind turbine which adjusts the angles of blades through a loop. The vertical axis wind turbine comprises multiple blades and the loop. The blades are hinged to supports on a motor spindle; pulleys are arranged on one vertical side of each blade, and the loop is wound on the pulleys on the multiple blades. The blades are hinged to the supports on the motor spindle, so that the blades can rotate, the centrifugal force generated by different positions of the blades is different, and thus the motor spindle is made to vibrate; the pulleys are arranged on one vertical side of each blade, and the loop is wound on the pulleys on the multiple blades; the rotation angles of the blades can be limited by the loop, and the difference between the centrifugal force of the blades is reduced, so that the vertical axis wind turbine can work stably; the blades can rotate, the blades on the return stroke is subjected by small wind resistance, and thus the utilization efficiency of the wind energy is greatly improved. The vertical axis wind turbine has the advantages of being simple in structure, convenient to maintain and low in cost.