The present invention provides a new and improved method for quickly and accurately determining the rotor blade angle of a wind power installation. The present invention also allows for the rotor blade angle measurements to be taken from the ground, thereby allowing the measuring equipment to be easily disconnected and transported to other sites. For example, a rotor blade angle of a wind power installation may be determined by using a spacing measuring device to measure the spacing between the rotor blade and the spacing measuring device. The measurements may then be processed in a computer to calculate the angle between the rotor blade and the spacing measuring device. Once this angle (the .alpha. angle) is ascertained, it may be compared to other values to assist in further adjusting the rotor blade angle.