With the increasing number of aerospace product models and the growing demand for personalized customization, the small-batch production mode has become increasingly common in the aerospace manufacturing industry. The low level of process maturity severely restricts both the efficiency of product development and the stability of quality. Therefore, this study aims to establish a scientific and systematic process maturity evaluation system in the context of small-batch aerospace manufacturing. This system can provide decision-making support for improving process capabilities and optimizing management in aerospace enterprises. This study used the Analytic Hierarchy Process (abbreviated as AHP) to an evaluation index system for the aviation manufacturing processes maturity, including target layer, First-level indicators, and Second-level indicators. The system includes four primary dimensions: process equipment, process review, production site, and project management, which are further refined into 26 s-level indicators. Expert scoring and pairwise comparison matrices are used to calculate the relative weights. This article evaluates and analyzes the process data of a certain aerospace product through practical application cases. The results show that “process review” is the most critical factor affecting process maturity (weight: 0.4674), with “process finalization” (weight: 0.1272) and “process verification” (weight: 0.1181) playing central roles. “Process equipment” ranks second (weight: 0.2983), with particular focus needed on improving “tooling design” and “equipment support.” The main innovation of this study lies in the use of AHP method to process maturity evaluation system for the small-scale aerospace production, and to prove the weight of the maturity evaluation system through specific practical operation methods.