The invention discloses a minimum backflow power phase shift control method for an isolated-type bidirectional DC converter, and relates to the technical field of power and electronic transformer control methods. The method comprises the following steps: enabling a control system to control a sampling chip to collect an output voltage V2 and an output current i2, and determining the output power of the converter through the output voltage V2 and the output current i2; obtaining a standard transmission power p through dividing the transmission power by the maximum transmission power PN of the isolated-type bidirectional DC converter; calculating an internal phase shift angle d1 according to different ranges of the standard transmission power p and a minimum backflow power; solving the difference between the output voltage V2 and a given output voltage V2ref, and obtaining an external phase shift angle d2 through a PI controller; carrying out the pulse generation according to the internal phase shift angle d1 and the external phase shift angle d2, and enabling the output voltage V2 to be constant through the closed-loop adjustment of the value of the external phase shift angle d2 The method is simple in control, and is easy to implement.