The present invention discloses an oil-gas separation cylinder, an oil-gas separation device and an oil chromatography. The oil-gas separation cylinder comprises an oil-gas separation cylinder body of which axe extends in direction of up and down, a separating block which separates the oil-gas separation cylinder body into an upper cavity and a lower cavity, an oil-gas separation cylinder piston movably installed in the lower cavity, an oil inlet passage and an oil outlet passage, and an oil-gas separation cylinder vent arranged at upper end of the upper cavity, wherein both of the oil inlet passage and the oil outlet passage are communicated with the upper cavity, wherein the separating block is provided with a guiding hole and a spaying hole used to communicate the upper cavity to the lower cavity, or the separating block is provided with a spaying hole guiding oil used to communicate the upper cavity to the lower cavity. By motion of an oil-gas separation cylinder piston, oil is spayed so as to rapidly realize equilibrium of oil and gas. Deaerating space is dynamically expanded so as to strengthen deaerating effect. The present invention adopts vacuum spraying method, but eliminates a mixer motor which continuously stirs the oil. Thus, structure of the oil-gas separation device is simplified.