The invention belongs to the technical field of optics, and provides a measuring device and method for double-resonance temperature condition of an optical cavity. The device comprises a laser source,a matching lens set, a dichroic mirror, a power meter, a cavity locking loop and a detector, wherein fundamental frequency light emitted by the laser enters the dichroic mirror after passing throughthe matching lens set, and then enters an optical parametric cavity through an output mirror of the optical parametric cavity after passing through the dichroic mirror; reflected light signals of theoptical parametric cavity are detected by a lock cavity detector of the cavity locking loop, and the cavity locking loop is used for locking cavity length of the optical parametric cavity according tothe reflected light signals of the optical parametric cavity; and the power meter is used for measuring power of frequency doubling light generated by the optical parametric cavity, and the detectoris used for receiving and detecting a transmission peak signal of the optical parametric cavity. The device and method have the advantages of being accurate in adjustment, convenient, visual and the like, and can be widely applied to the field of optical parametric cavity application.