The invention discloses a detection device for the gap tooth angle of an automotive torsion bar spring. The detection device comprises a worktable, a left support, a right support, an alidade and a main dial, wherein guide rails are arranged on two sides of the worktable, and the left support and the right support are fixed to the guider rails on the two sides of the worktable and can move on the guide rails; a right spline sleeve is fixed in the right support, and a right spline sleeve inner hole is matched with a torsion bar spring right spline; the main dial is installed in the left support and can rotate in a hole formed in the left support, the diameter of the hole in the main dial is larger than the outer diameter of the torsion bar spring, a small protruding outer circle is arranged on the left of the main dial, a notch is formed in the alidade and matched with the small protruding outer circle of the main dial and can rotate on the main dial, a left spline sleeve is fixed in the alidade, and a left spline sleeve inner hole is matched with a torsion bar spring left spline. The detection device for the gap tooth angle of the automotive torsion bar spring is convenient to use, and can relieve labor intensity and improve machining accuracy.