Interferometric Synthetic Aperture Radar (InSAR), a highly effective technique for surface deformation monitoring, has been extensively employed in applications such as geological disaster monitoring, mining surface damage. Nevertheless, InSAR is limited by its ability to measure only one-dimensional deformation along the satellite's Line-of-Sight (LOS), which restricts its capacity to capture the full complexity of surface movements. This study focuses on Kilauea Volcano and utilizes three sets of Synthetic Aperture Radar (SAR) data acquired from different orbital directions before and after the volcanic eruption, in conjunction with data from several Global Navigation Satellite System (GNSS) monitoring stations. The two-orbit DInSAR observation method is used to calculate vertical and east-west deformations, whereas the three-orbit DInSAR observation method is employed to calculate vertical, east-west, and north-south deformations. The consistency of the vertical deformation and east-west deformation calculated by both methods is tested via the Intraclass Correlation Coefficient (ICC), and the deformation calculation accuracy is validated by monitoring data from two GNSS stations, KAMO and KTPM. To further discuss the computational accuracy of the two-orbit and three-orbit methods, the Probability Integral Method (PIM) is used in conjunction with SAR spatial parameters to simulate LOS deformations in different directions, allowing for 2D/3D deformation accuracy analysis. The experimental results indicate that: (1) the vertical (ICC=0.986) and east-west (ICC=0.989) deformations calculated by the two and three-orbit DInSAR observation methods are highly consistent, with maximum RMSE differences of 0.021 m and 0.013 m, respectively; (2) the absolute errors of the vertical, east-west, and north-south deformations calculated by the three-orbit method compared with the GNSS monitoring data from the KAMO and KTPM stations are relatively small, at 0.04 m, 0.035 m, 0.009 m, and 0.001 m, 0.023 m, and 0.0002 m, respectively; and (3) the simulation experiment reveals that, in the absence of spatial parameter errors, the three-orbit method can accurately calculate three-dimensional deformations; the error in the subsidence calculation using the two-orbit method is about 3% of the maximum subsidence value, and the error in the east-west horizontal movement is about 5% of the maximum horizontal movement value, indicating that the two-orbit method can provide relatively accurate vertical and east-west surface deformation measurements.