The invention discloses an OFDR (Optical Frequency Domain Reflectometer)-based silicon optical chip temperature measurement device and method. The device comprises a linear sweep frequency laser device, an optical fiber beam splitter, an optical fiber circulator, a silicon optical chip, a spot-size converter, an optical fiber coupler, a photoelectric detector, a data acquisition card and a computer. The measurement method disclosed by the invention is based on an optical frequency domain reflection technology, and the silicon optical chip to be measured is used as a sensor; light gets into andgets out of the chip through the spot-size converter of a special structure. A temperature change can cause Rayleigh scattered spectrum movement of the chip; and a movement amount is obtained by cross-correlation operation of measuring a Rayleigh scattered spectrum (after the temperature varies) and a reference spectrum (original temperature). A cross-correlation peak deviation value is the movement amount corresponding to a temperature variation. The measurement method has the characteristics of high spatial resolution and high precision; the problems of complicated sensor layout of a traditional sensing measure, external influence easily caused on a measurement result and the like are solved; and the measurement method is particularly suitable for measuring the temperature of the tiny silicon optical chip.