设计了太赫兹合束的空间几何模型，计算模拟出了单束、2×1双束以及2×2四束太赫兹束的空间合束图像，并研究了接收距离、高斯光束峰值间距与太赫兹束干涉强度的关系，以及束间相位差对合成的影响.结果表明:2×1、2×2合束模式的峰值强度增大倍数近于4倍和16倍；2×1模式和2×2模式对应的最优太赫兹合成的观测接收距离分别为0.325 m和0.223 m；光束间距与合成峰值光强成非线性反比关系，不存在最大值或最小值临界点.对2×1模式进行了存在束间相位的合束模拟，得到束间相位差与合成强度的关系，并于相位差为π时达到最小值，故束间相位差虽不可避免，但可以减小.

Space combining beam of Terahertz was designed in the paper. The optical intensity of single THz beam, double THz beams (2×1) and four THz beams (2×2) were calculated in the condition of spatially combining images. Through the obtained images, the relationship between the receiving distance, the Gaussian beam peak separation distance and combining intensity were obtained, and the effect of phase difference on combining beam was analyzed. The results show that THz peak intensity is enhanced by near four and sixteen multiples in the conditions of 2×1 and 2×2 arrangements. The optimal THz beam receiving distances of 2×1 and 2×2 arrangements are found through calculation and images, and they are 0.325 m and 0.223 m. Gaussian beam peak separation distance and peak intensity are nonlinearly inverse relationship, which has no maximum or minimum points. The image of 2×1 arrangement was achieved when there is phase difference between two THz beams, and the minimum point of THz intensity of π was attained in the image. So it can be concluded that the phase difference can be decreased but it can not be avoided.