Vacuum leakage is extremely harmful to aircraft and needs to be discovered as soon as possible. Aiming at the problem of vacuum leakage location, this paper proposes a cross-correlation wavenumber domain imaging method. This method obtains the time-space domain information of the leakage elastic wave through the array sensor and transforms it into the frequency-wavenumber domain through the three-dimensional Fourier transform. The direction of the maximum value of the wavenumber vector represents the direction of the leakage source. In the algorithm, the cross-correlation operation is added, and the synchronous acquisition of multiple array elements is replaced by the polling scan method, which greatly improves the possibility of the realization of the algorithm. A 64-element ultrasonic sensor was fabricated and the method was verified. The results show that the method proposed in this paper can realize the continuous leakage signal direction of the planar structure and is applicable to the leakage holes of different apertures, and it has the potential for application on orbiting spacecraft and aircraft.