The utility model pertains to an inspissated oil sampling case, in particular to a constant temperature sampling case used in an inspissated oil pipeline. The constant temperature sampling case consists of a sampling case door, a sampling case body, a hand button, a pin and a hinge. The utility model is characterized in that the sampling case body is connected with the sampling case door by the hinge and the sampling case door is provided with the hand button one side of which is provided with the pin to fix the sampling case door. The constant temperature sampling case used in an inspissated oil pipeline makes use of the high heat of the inspissated oil pipeline to maintain the oil inside a sampling pipe at a high temperature to avoid solidification and facilitate sampling and daily production in oil field.