The mismatched-pins inspection of complex aviation connector is a critical process to ensure the correct wiring harness assembly, of which the existing manual operation is error-prone and time-consuming. Aiming to fill this gap, this work proposes an augmented reality (AR)-assisted deep learning-based approach to tackle three major challenges in aviation connector inspection, including small pins detection, multi-pins sequencing, and mismatched pins visualization. Firstly, the proposed spatial-attention pyramid network approach extracts image features in multilayers and searches for their spatial relationships among images. Secondly, based on the cluster-generation sequencing algorithm, these detected pins are clustered into annuluses of expected layers and numbered according to their polar angles. Lastly, AR glass as the inspection visualization platform, highlights mismatched pins in the augmented interface to warn operators automatically. Compared with other existing methodologies, the experimental result shows that the proposed approach can achieve better performance accuracy, and support operator's inspection process efficiently.