In this paper, we introduced a light-transmitting fiber with a large numerical aperture and core diameter to solve the problem that the traditional measurement systems for laser spot distribution restricted the incident angle of beams. Then, the fiber array was arranged as the front end of spot sampling in the system, so as to increase the allowable incident angle range and analyze the associated light-transmitting characteristics. Furthermore, we analyzed the influencing factors of optical fiber transmittance and studied the tolerance for the incident angle of optical fiber transmission and the consistency of optical fiber as an array unit by combining numerical analysis method and experimental measurement. This verified the feasibility and superiority of optical fiber applied in the measurement systems for laser spot distribution. The results can provide an effective theoretical basis for the establishment of perfect optical fiber integrated equipment and its application to the relevant laser measurement systems.