The invention discloses a thermal expansion coefficient detection method for an anchor cup. The detection method comprises the following steps: 1, selecting a plurality of groups of fiber grating sensors, wherein each group comprises a fiber Bragg grating strain gauge and a fiber Bragg grating thermometer; 2, putting the strain gauges, thermometers and anchor cup in a water bath temperature box according to different combination modes; 3, recording wavelength value of the strain gauges and thermometers before temperature rise in each combination mode; 4, heating to 60 DEG C, measuring the wavelength value of the strain gauges and thermometers once every change of 2-3 DEG C, and recording the wavelength value; and 5, calculating the thermal expansion coefficient of the strain gauges or anchor cup in different combination modes according to the measured value in the step 4.