Reliable linear actuation (LA) driving plays an important role in scientific studies and practical applications. To realize the frequency-convertible and accurate directional linear displacement of the LA under low-frequency symmetric wave excitation, frequency-convertible double orthogonal piezoelectric wafer oscillators (FCDOPWOs) are proposed and studied as the driving elements of the LA, which achieve the frequency-convertible performance by adjusting the mass of FCDOPWO, conveniently. The dynamic mechanism is modeled and the motion trajectory of the driving foot is simulated. The resonant frequency of the LA is analyzed theoretically and controlled by mass-adjustment of FCDOPWO. The optimal vibration mode is obtained for the experimental verification studies. Under the excitation of a square wave, LA achieves stable forward motion. By controlling the voltage difference and frequency of the excitation of FCDOPWO, the elliptical trajectory of the driving foot is realized. Experimental results show that the resonant frequency of the actuation method is reduced by 24%, taking the resonant frequency of the LA with the single mass block as a benchmark. The maximum average speed of LA is 15.62 mm/s under the excitation of a 50 Hz square wave. The resonant frequency of LA is reduced by mass-adjustment of FCDOPWO to achieve the fast-positioning capability at a lower frequency, which enhances the potential industrial applications of the piezoelectric actuation.