The disclosure discloses a linear oscillatory machine control method based on an adaptive full-order displacement observer. The method includes the following steps: a full-order displacement observer is constructed; the system equivalent spring elasticity coefficient and equivalent damping coefficient are used as parameters to be identified, the full-order displacement observer serves as an adjustable model, and the machine itself serves as a reference model; an error state equation is constructed based on the error of the adjustable model and the reference model; Popov's hyperstability theory is adopted to obtain the operation upper critical frequency and the adaptive formula of adjustable parameters that make the error state equation converge; the machine is operated at a frequency lower than the upper critical frequency, the machine current and voltage signals measured during the operation process are input into the full-order displacement observer, thereby realizing frequency tracking and displacement control.