The invention discloses a precise measuring head based on a parallel compliant mechanism. The precise measuring head comprises an annular shell. The top part of the shell is provided with an upper end cover. The center of the internal side of the upper end cover is provided with an object carrier in a hoisting way. The bottom part of the shell is connected with the parallel compliant mechanism. The center of the parallel compliant mechanism is provided with a measuring rod. The end part of one end, which is away from a moving platform, of the measuring rod is provided with a measuring ball. Three mobile reflecting mirrors are evenly distributed at the center of the parallel compliant mechanism. Three laser interferometers are evenly distributed on the side wall of the object carrier. The object carrier is provided with fixed interference mirrors below the laser interferometers. Each laser interferometer is aligned with one fixed interference mirror. The common elastic support is replaced by the parallel compliant mechanism so that the structure of the measuring head is simplified, the clearance and the friction between the parallel compliant mechanism and the shell can be greatly reduced and the precision of the measuring head can be enhanced. The structure of the parallel compliant mechanism is integrated so that miniaturization of the structure of the measuring head is also facilitated and the influence of its own gravity on measurement can be reduced.