The invention provides a fabric tightness detecting apparatus. The fabric tightness detecting apparatus comprises an apparatus body, the apparatus body is connected to a PLC industrial control machinearranged at the outer part of the apparatus body in a communication mode, the apparatus comprises a
desk body, and further comprises a
light source mechanism, a test box and a light receiving mechanism arranged on the
desk body. The
light source mechanism is arranged on one side of the top of the
desk body, the light receiving mechanism is arranged on the other side of the top of the desk body, the test box is arranged between the
light source mechanism and the light receiving mechanism, and central axial lines of the light source mechanism, the test box and the light receiving mechanism areon a same
vertical plane. The fabric tightness detecting apparatus is based on a box method principle of
light transmission, detecting is simple, detecting quantity is small, manual labor intensity islowered, the detecting efficiency is improved, and meanwhile, accuracy of detecting results is further improved, stability and reliability are high, and the fabric tightness detecting apparatus has good practical values.