The invention provides a heavy oil two-stage reactor hydrocracking process. A heavy oil raw material, a catalyst and a vulcanizing agent are uniformly mixed, then the mixture is mixed with high-pressure hydrogen to enter a first-stage hydrocracking reactor for a reaction, and the catalyst, dehardening/circulating tail oil and the vulcanizing agent are uniformly mixed in a second feed tank, and then mixed with a hydro-upgrading liquid product discharged by the first-stage hydrocracking reactor through a delivery pump, the mixture is injected into a second-stage hydrocracking reactor for a reaction, which reduces the content of colloid and asphaltene in heavy oil and coking tendency of the heavy oil in the second-stage hydrocracking reactor, can improve the coking potential of the heavy oil,and prolongs the service life of the catalyst in the second-stage hydrocracking reactor; the desulfuration and denitrification effects in the second-stage hydrocracking reactor are improved; the reaction characteristics of the heavy oil in the first-stage hydrocracking reactor and second-stage hydrocracking reactor are matched with a catalytic function of the catalyst, the activity of the catalyst is optimized, low-sulfur and low-nitrogen high quality fuel oil can be produced, and the running cost of the hydrocracking technology is reduced.