Fizeau wavelength measurement plays an important role in the fields of laser technology, optical communication, and optical metrology. The accuracy of the traditional multistage Fizeau wavemeter is limited owing to the degradation of the stripe symmetry and finesse caused by variations in the cavity length. Herein, we propose a virtual Fizeau cavity (VFC) based on the principle of phase difference to address this issue. The principle analysis and simulation of this measurement system are presented, along with experiments that verified the feasibility and performance of the VFC method. The wavelength measurement accuracy of this system is superior to 60 MHz in the 350-1100 nm wavelength range. The design concept of "virtual-real combined" cavities first proposed in this paper to our knowledge introduces possibilities for the development of high-accuracy Fizeau wavelength measurements.