Abstract：We propose a method of simultaneous ambiguity resolution based on multi-antenna network for single epoch, applying the following steps. Firstly, wide lane ambiguities from each baseline with length constraints are resolved synchronously, and the approximate baseline vector of the dm~cm level precision is obtained. Then, the basic frequency ambiguities of each baseline are resolved with the wide-lane baseline components constraints, and the mm level baseline components are derived. The key of this approach is to verify that wide lane ambiguities are correct, namely, the priori information for resolving the basic frequency ambiguities is accurate. Owing to few observations for one epoch, the tested ambiguity using only ratio is not reliable. A comprehensive judging criterion combining baseline error, mean square error of weight unit, the closed loop of baseline network, and ratio value is proposed; this can avoid accepting the wrong ambiguity and rejecting the correct ambiguity. The successful rate of ambiguity resolution using the above-mentioned algorithm is increased by 1%~2%. More navigational information for the mobile platform can be obtained and its service ability can be improved.