The present invention relates to the field of rail transportation and discloses a dynamic decoupling and coupling control method and device for trains based on energy-saving virtual formation. The method realizes decoupling and coupling by adjusting the speeds of the front car and the rear car for trains requiring virtual decoupling or virtual coupling, wherein the spacing of the front car and the rear car can be controlled according to different applications based on the line conditions of the front car and the rear car after decoupling and before coupling; at the same time, the present invention takes the minimum safe tracking distance as the basis for the completion of decoupling or coupling, and improves the calculation of the minimum safe tracking distance method. The present invention can obtain a more accurate minimum safe tracking distance between trains, realize flexible changes in decoupling or coupling of trains in different application scenarios, and improve the operational efficiency of trains.