The invention provides a device for measuring gel time of prepregs, which is characterized by comprising glass fiber fabrics, wherein the glass fiber fabrics are pasted and covered on the upper side and the lower side of a sample; a thermocouple is inserted in the middle of the sample, and is connected with a thermodetector; heat pressboards are used for applying pressure to the sample from the upper side and the lower side and heating the sample; a positive electrode and a negative electrode are respectively arranged among the upper side and lower side of the sample and the heat pressboards; the positive electrode is connected with the negative pole of a power source; the positive pole of the power source is connected with a resistor; the resistor is connected with an ampere meter and then connected with the negative electrode. The device for measuring the gel time of the prepregs has the advantages that the accuracy rate is high, and the efficiency is high, and can also be used for measuring the gel time of resin.