A laser power scale transfer technique was developed based on shape detection; using this technique, detectors can be precisely centered on laser beams, thereby significantly reducing measurement errors introduced by detector nonuniformities and misalignments. A modified imaging scheme was designed and embedded in the scale transfer setup, and the effective resolution was proven to be better than 100  μm, compatible for incident lasers with diameters under 15 mm. For different types of detectors, absolute positioning was realized using objective algorithms with repeatability errors of 7 to 13  μm, which is an improvement of over 30 times the limitation of human-vision-based positioning. Correspondingly, the relative measurement error caused by detector non-uniformity for a typical calibration was reduced by a factor of 19–40 in the scale transfer process. The proposed technique thus has the potential for detector-based optical metrological applications that are influenced by geometric accuracy.