The invention discloses a long nozzle argon blowing refining device capable of effectively removing tundish inclusions. The device is composed of a long nozzle, a swirling chamber and a swirling chamber outlet. An annular groove is reserved in the position, close to the top, of the inner wall of the long nozzle. An annular dispersion gas inlet chamber is arranged in the annular groove and connected with an argon conveying system through gas inlet holes formed in the wall of the long nozzle. The lower portion of the long nozzle is connected with the swirling chamber in the tangential direction.According to an argon blowing refining method adopting the device, the inclusions are removed by means of the adhering effect of dispersed phase argon bubbles, and the problems that a traditional argon blowing device is large in bubble size, the time of standing in molten steel is too short, the casting powder surface is prone to being broken, and consequentially, secondary oxidation and heat loss of the molten steel are caused are solved; and in addition, long nozzle argon blowing prevents scaffolding blockage of the long nozzle to a certain extent, meanwhile, gravitational potential energyof the molten steel in the swirling chamber is converted into rotational kinetic energy, the inclusions are promoted to collide, grow up and float upwards before being removed, and accordingly, the cleanliness of the molten steel is improved.