The invention relates to a multi-freedom-degree adjustable spray pipe assembly device which comprises a supporting frame, an adjusting vertical plate I, a moving rod, a combined acorn nuts, a thrust block, an adjusting vertical plate II, a working platform, an arc-shaped frame and a scale plate. The adjusting vertical plate I and the scale plate penetrate a vertical through groove through a bolt to be fixedly connected, and the adjusting vertical plate I can be adjusted in the vertical direction by adjusting the position of the bolt in the vertical through groove. Displacement adjustment of the arc-shaped frame on the working platform in the horizontal direction is achieved by adjusting the positions of bolts in horizontal through grooves. Displacement adjustment of the adjusting vertical plate II on the working platform in the horizontal direction is achieved by adjusting the positions of bolts in the horizontal through grooves. The multi-freedom-degree adjustable spray pipe assembly device is suitable for fixing and limiting of solid rocket engines of different lengths and sizes in the horizontal direction, and therefore displacement adjustment of the solid rocket engines in the horizontal direction is achieved; and a threaded rod is rotated by rotating a rocking handle, and ascending or descending adjustment of the working platform is achieved.