Field of view (FOV) is the basic parameter of sun-photometer and also the key parameter for transfer calibration and inter-comparison of sun-photometers using an integrating sphere as light source in the laboratory. Obtaining high-precision FOV is important to improve the accuracy of sun-photometer calibration. Based on the matrix measurement method, a system using laser as a light source to measure the FOV of CE318 sun-photometer is developed, and then the FOV results of matrix method are compared with the transfer calibration method. The results indicate that the matrix measurement with laser has a FOV uncertainty of 0.4%～1.1%. Because of the movement during measurement process and divergence angle of sun, the FOV uncertainty based on matrix measurement with sun is about 1.3%～1.4% which is larger than the laser result. In addition, the more historical calibration records, the more accurate FOV can be obtained by using transfer calibration method by comparing with matrix approach with laser, which suggests that the transfer calibration method can obtain accurate FOV when historical records are enough.