Sensitive information has become a bottleneck of enterprises' collaboration, especially to competitive enterprises' collaboration. How to make collaborative decision under the protection of sensitive information is an important problem to advance enterprises' collaboration. To investigate the problem, a collaborative ordering of enterprises with differentiated products is modeled to get the optimal ordering. The model's computation needs the information of cost and demand which other enterprises are unwilling to provide. So a secure computation protocol under the protection of cost and demand information is designed to compute the optimal ordering of collaborative enterprises. The result shows the decision of complete information sharing can be achieved even without leaking the sensitive information through using the secure computation protocol.