The invention relates to recycling of oil field vent natural gas, and particularly relates to a device for recycling vent natural gas in the production process of an oil-gas field. The device comprises a filter, a one-way gas valve, a gas buffer tank, a self-operated pressure valve, a compressor, an evaporator, a hydration separating unit, a gas storage tank, a bi-directional gas valve, a stop valve, a slurry pump, a screw pump, a laval spray valve, a surface active agent storage tank, a crusher, an ice-making device, a vertical type three-phase separator, a storage cavern, an air cooler, a throttle valve, a flow distributor, a water pump, a one-way valve, a bi-directional valve, a gas-liquid separator, a hydration recycling unit and a saturation stability unit. Through material cycle and refrigeration cycle of the device, the vent natural gas can be effectively recycled.