The invention discloses a negative-pressure transformer oil chromatographic analysis standard oil preparation device and method. The device comprises a standard oil preparation tank and an air cylinder, wherein the standard oil preparation tank is provided with an overflow opening; the top in the standard oil preparation tank is provided with an air bag; the air bag is connected with the air cylinder; a standard gas is arranged below the air bag; transformer oil is arranged below the standard gas; the overflow opening is positioned at the junction of the standard gas and the transformer oil and used for quantifying the transformer oil; the standard oil preparation tank is provided with a linear motor; two ends of the linear motor are connected to the bottom and the middle standard gas part of the standard oil preparation tank for oil and gas circulation. The negative-pressure transformer oil chromatographic analysis standard oil preparation device and method, which are provided by the invention, are used for overcoming the defects that transformer oil chromatographic analysis standard oil prepared at normal pressure is difficult to store, the concentration of standard oil prepared from standard gases with the same concentration is single, and the like, and have the characteristics of convenience in preparation, adjustable standard oil concentration range, and long-term storage of standard oil.