The invention provides a quick-open type oil well sampling device. An oil inlet is formed in one side of a valve body and connected with an oil inlet pipe, and the oil inlet pipe is a double-layer pipe body with an anti-freezing vacuum interlayer, so that the heat preservation effect is good; a valve element perpendicular to the oil inlet is arranged in the center of the valve body, an L-shaped oil path channel is formed in the center of the valve element, an inlet of the L-shaped oil path channel corresponds to the oil inlet in position, and an outlet of the L-shaped oil path channel is formed in the lower end of the valve body and communicates with the outside; and a square handle is arranged at the upper end of the valve body and connected with the valve element. The handle is used for driving the L-shaped oil path channel in the valve element to rotate by 90 degrees, and then the inlet is aligned with the oil inlet pipe so that sampling can be conducted; operation is convenient, and a sealing part is resistant to cold and heat and high in aging resistance; the structure is compact, the handle is detachable, the occupied space is small, the capacity of the L-shaped oil path channel is small, the accumulation of crude oil in the valve body is reduced, operation is convenient, and the sampling effect is good.