The invention discloses a fiber grating sensor insert for injection molding product detection and a manufacturing method thereof. The insert comprises a temperature fiber grating, a strain fiber grating, grating encapsulators, protection layers and connectors; the temperature fiber grating and the strain fiber grating are arranged side by side, the temperature fiber grating comprises a plurality of conducting fibers and a plurality of grating unit zones, the strain fiber grating comprises a plurality of conducting fibers and a plurality of grating unit zones, the conducting fibers and the grating unit zones are disposed at intervals, the grating encapsulators protecting the grating unit zones are disposed on the temperature fiber grating and the strain fiber grating, the protection layers wrap the conducting fibers, and ends of the temperature fiber grating and the strain fiber grating are provided with the connectors. The insert can be conveniently and reliably implanted in a product injection molding process, so a temperature sensor and a strain sensor are buried in a product, the sensors can be positioned, and the sensors can be guaranteed to be live in a high-temperature and high-voltage condition of injection molding; and the sensors are seamlessly embedded into the product, so measurement accuracy and the service lives of the sensor can be substantially improved.