The utility model discloses a system for it is used for ammonia plant of chemical fertilizer factory to retrieve useless hydrogen of oil plant relates to oil plant, the hydrogen comprehensive use of resources technical field of chemical fertilizer factory. This system is used as the hydrogen resource among the ammonia plant of chemical fertilizer factory with the hydrogen -rich gas and the surplushydrogen of oil plant, hydrogen resource through with between oil plant and the chemical fertilizer factory is jointly optimized, it is with high costs to solve the oil plant hydrogen wasting of resources and chemical fertilizer factory's ammonia plant hydrogen manufacturing, the problem that the energy consumption is high, when guaranteeing the ammonia plant even running, can utilize oil plant hydrogen -rich gas and surplus hydrogen by effective recycling, can reduce ammonia plant hydrogen manufacturing cost and energy consumption again, thereby improve economic benefits and overall energy utilization level.