The optic interference experiment and testing inspection systems with fiber dot light sources need the fewest optical components, have the best environmental and mechanical stability，and can get highprecision benchmark spherical wave so that there are the minimum errors for the system. For this purpose, the factors that influence the quality of optical fiber dot light source are analyzed. Applying the basic theory of light transmission in fiber, the method to improve the performance of fiber dot light source has been found. By the way of digital holography, the interference patterns of spherical wave produced by two fiber dot light sources are analyzed and computed, and the precision of the spherical wave is evaluated. The results show that the spherical wave produced by fiber dot light sources can meet the requirement of general interference inspection system on precision of benchmark spherical wave.