The invention discloses a totally-engaged double-vortex tooth with gradually-changed wall thickness. An engaged molded line of a first fixed vortex tooth (1) is in smooth connection through four sections of curves. The four sections of curves comprise an equal-distance curve H1I1 of a first variable-diameter base circle involute, an equal-distance curve H1G1 of a first circle involute, an equal-distance curve G1M1 of a second circle involute and an equal-distance curve M1N1 of a second variable-diameter base circle involute. A second fixed vortex tooth (2) and the first fixed vortex tooth (1) are completely the same and are rotated clockwise by 90 degrees with the center point O as the center to obtain a first movable vortex tooth (3) and a second movable vortex tooth (4). In the work process, the movable vortex teeth and the fixed vortex teeth are completely and correctly engaged. According to the provided totally-engaged double-vortex tooth with the gradually-changed wall thickness, the air inflow of a vortex compressor can be increased, the area utilization rate is increased, the compression ratio is increased, the work performance of the vortex tooth is improved, and designing and machining of the vortex tooth are facilitated.