Disclosed is a method for improving a communication success rate in a simultaneous call trial between subscribers in a mobile communication system. The method includes receiving by a second subscriber network an IAM message from a first subscriber network when a first subscriber tries a call to a second subscriber; determining by the second subscriber network whether the second subscriber has requested a termination to the first subscriber, after receiving the IAM; aborting by the second subscriber network an originating call trial of the second subscriber when the second subscriber has requested the termination; trying by the second subscriber network a page to the second subscriber after aborting the originating call trial; and setting a call between the first subscriber and the second subscriber by the first subscriber network and the second subscriber network, after succeeding in paging the second subscriber.