Abstract: This paper deals with the application of a posteriors variance estimation in space resection of a single photograph.In this case the weights to be estimated are those of the ground coordinates and of the image coordinates.If the ground coordinates have equal variances such as the signalized points,we may consider them as fixed points rather than weighted observations and needn't perform a posteriors variances estimation.But if their variances are not equal,such as in the case of using natural objects(the images of which have to be identified and transferred),they should be regarded as weighted observations and their variances should be estimated point by point.In this way the accuracy of adjusted results can be improved.