Flight testing is the most authentic and effective ultimate means for aircraft design verification and certification. The main landing gear of a certain large aircraft employs a novel tandem multi-strut configuration, featuring complex structural load transmission and landing impact loads, which presents significant technical challenges for flight verification. This paper analyzes the structural characteristics of this tandem multi-strut landing gear and the collaborative load-bearing behavior among the struts, designs load-measuring strain gauge bridges, and specifically develops an "integrated" load calibration scheme that includes calibration conditions simulating the collaborative load-bearing relationships between struts. To address the issues of numerous variables and large data volumes in the analysis of strain gauge bridge load response characteristics, a novel method for evaluating the linearity of strain gauge bridge load response through partial correlation coefficients is developed. The concept of robustness for load measurement models that accounts for the influence of calibration errors on measurement results is proposed, and its mathematical evaluation index is derived. A new load measurement modeling method is constructed based on weighted averaging and ranking of the response coefficients and partial correlation coefficients of strain gauge bridges, which can simultaneously consider both robustness and goodness of fit. Typical landing impact loads of an aircraft measured using this model are presented, their variation patterns are qualitatively analyzed, and their magnitudes are quantitatively evaluated. The results demonstrate that the landing gear load calibration and modeling method is correct and can serve as a reference for relevant engineering technicians; the measured landing impact load variation patterns are clear and reasonable, and the values are correct, providing an important basis for design certification and improvement.