An epitaxial Ba(2)NaNb(5)O(15) thin film with excellent crystalline properties has been achieved on a (001) KTiOPO(4) substrate by use of the technique of pulsed laser deposition. X-ray-diffraction analysis has revealed that (110)-oriented Ba(2)NaNb(5)O(15) film was produced. The film has good optical transmitting characteristics and a propagation loss as low as 1.08 dB/cm. The noncritical phase-matching feature in the second-harmonic generation process in the film waveguide has also been studied.