This invention discloses using SPR technology to simultaneously and quantitatively measure the concentrations of different sex hormones in a serum sample, which can be used to evaluate different clinical situations. It also discloses an efficient formula to make a mixed SAM that can greatly enhance the immobilization ability of the metal surface in SPR based techniques, which is good for the immobilization of relevant antibodies used for the detection of representative sex hormones in a serum sample.