The present invention provides a method of fast image construction. The wavelength information is extracted in advance based on characteristics of a Fourier domain Optical Coherent Tomography (OCT) system, to obtain a vector of wavelengths which are in a uniform distribution in a wave number space, and thus to obtain a virtual position coefficient of this wavelength vector at a CCD, from which a weight matrix is calculated based on a transfer function for a discrete Fourier transform with zero-padding interpolation. In operation of the system, the interpolation is carried out based on the weight matrix and collected data, or is carried out based on the weight matrix which has been truncated by being subject to windowing and the collected data, to obtain interpolated data satisfying requirements. The method according to the present invention is simple and easy to implement, by which, it is possible to improve the precision and speed of the Fourier domain OCT data process, and thus to improve the capacity of real-time image reconstruction of the Fourier domain OCT system.