An optical parametric oscillator (OPO) based on periodically-poled lithium niobate (PPLN) and pumped by 1064.2-nm laser is demonstrated, which can be conveniently tuned by the means of changing its operating temperature. The parameters of the set-up and experimental results are introduced in this paper. We adjusted the operating temperature from 80 to 250 ℃, the output wavelength shifted from 1485.4 to 1540.7 nm. The average of the shifts is 0.33 nm/℃.