This invention relates to a lockup structure of mobile hard drive, and comprises a base plate for receiving a hard drive, a lock member having a block sheet, a base frame having a through hole for mounting the lock member, and a spiral arm. At a free end of the spiral arm comprises a protruding block for locating into the base plate and a notch for positioning the block sheet of the lock member, and at a fixing end comprises a position block mounted into a shell. Thus, when in locking position, the spiral arm cannot be pushed outwardly and the position block can prevent the base plate from withdrawing from the shell, therefore, a wrong withdrawal will be avoided.