A hexanary-feedback contention access method is provided in a wireless network having at least one base station capable of distinguishing at most 5 mobile stations concurrently requesting for register. A random procedure determines whether each mobile station is allowed proceeding contention access at a subsequent slot. The quantity of mobile stations capable of proceeding contention access at the subsequent slot is defined as a current mobile station quantity. If the quantity is from 2 to 5, a random procedure is performed based on the quantity to determine whether a contention access is proceeded at a subsequent slot. The mobile station quantity is then detected and if the quantity is 1, the mobile station is allowed for registration and the current mobile station quantity is decremented. If the current mobile station quantity is not equal to 0, the random procedure is repeated based on the current mobile station quantity.