The utility model belongs to a crude oil collection and transmission device, in particular relates to a volatile hydrocarbon steam recovery device for the oil tank of the crud oil collection and transmission technical system. The utility model is characterized in that a sedimentation tank (1) is communicated with a constant pressure buffer tank (3) through a pipeline, and the constant pressure buffer tank (3) is communicated with a condensing tank (4) through a pipeline; the top part of the constant pressure buffer tank (3) is connected with a SY frequency converter (6), and connected with a suction compressor (9), the suction compressor (9) is communicated with a suction rear cooler (10), the suction rear cooler (10) is communicated with a gas liquid separator (11), and the gas liquid separator (11) recovers the gas after separation to a light hydrocarbon recovery device through a pipeline; the gas liquid separator (11) communicates the liquid phase after separation and the condensate separated from the constant pressure buffer tank (3) to the condensing tank (4) through a pipeline, and the condensing tank (4) is communicated with a liquid hydrocarbon pump (5). The device can realize the recovery to the volatile oil gas from the crude oil tank, which makes the failure rate of the technological process low, and the process is safe and reliable.