The invention discloses a common rail system oil atomizer which comprises an oil atomizer body, an electromagnet, a ball valve arranged on a restriction orifice, a floating sleeve, a needle valve spring, a needle valve and a needle valve body. An oil containing groove communicated with an oil inlet channel is formed between the needle valve and the needle valve body, the upper portion of the needle valve is used as a control piston, the upper portion of the needle valve is sleeved with the floating sleeve, a control cavity is formed among the floating sleeve, the bottom face of the restriction orifice and the top end face of the needle valve, an oil inlet hole is formed in the restriction orifice and communicates the control cavity and the oil inlet channel, and an oil outlet hole communicated with the ball valve is formed in the restriction orifice on the top of the control cavity. According to the common rail system oil atomizer, the control piston and the needle valve are connected into a whole, response is fast, the control precision is high, the structure is simple, machining is convenient, and manufacturability is good. No static state leakage exists in needle valve matching parts and control piston matching parts, the requirements for pump oil of an oil supply pump can be reduced, adaptability to the oil quality is good, and the reliability is improved. The needle valve is directly controlled by the control valve to act, the response speed of the oil atomizer is higher, the precision is higher, and therefore the multi-injection capacity is high.