The invention discloses a concrete expansion joint construction hydration process monitoring method in a severe cold region, and belongs to the field of civil engineering. The monitoring method includes the steps that a time-temperature data sequence is acquired through laboratory and site tests, fitting is conducted, and apparent activation energy is figured out; then fitting is conducted on age-strength data obtained in a laboratory, the strength field of the expansion joint is acquired through an equivalent age method, and the decision of maintenance termination or traffic opening is made based on the part with the weakest strength in the strength field. By means of the concrete expansion joint construction hydration process monitoring method in the severe cold region, the strength of concrete can be fully developed, and occurrence of early damage to concrete is avoided; moreover, design, preparation and maintenance of the mix proportion of concrete can be guided, so that there is an expected temperature field in concrete, and expected strength is achieved at the set age; it can be ensured that the position with the weakest strength in the strength field can be accurately judgedout in spite of the special condition of the expansion joint in the severe cold region.