Joint three-dimensional location algorithms aim to simultaneously obtain the north, east, and height coordinates of each pixel in several adjacent Interferometric Synthetic Aperture Radar (InSAR) scenes. Joint calibration is a key procedure used to achieve an accurate three-dimensional location. It can ensure the continuity of three-dimensional locations among adjacent scenes, and achieve the location of large areas with few Ground Control Points (GCPs) using Tie Points (TPs). In this paper, a new joint calibration algorithm for airborne interferometric SAR that simultaneously calibrates north, east, and height coordinates is proposed. It employs a weighted optimization method to carry out calibration, and introduces weights to calibration to discriminate GCPs and TPs with different coherences and locations. The experimental results for airborne InSAR data show that the three-dimensional location accuracy obtained using the proposed calibration algorithm is better than that obtained using the traditional method.