Abstract: After analyzing the characters of diesel in oil vapor absorption process, a concept of low temperature critical absorption technology for oil vapor recovery using diesel as absorber is brought up in this article. A corresponding technology has been developed as well. The use of this technology on the vent gas from sour water tank in JLPEC has received significant results. The recovery rate of oil gas in the vent gas from sour water tank reaches to 95% and above. Currently the technology has been widely used.