A parameter adjustment method includes an acquisition process and a parameter changing process. The acquisition process acquires, from an inspection apparatus configured to inspect a combined substrate in which the first substrate and the second substrate are bonded by the bonding apparatus, an inspection result indicating a direction and a degree of distortion occurring in the combined substrate. The parameter changing process changes at least one of multiple parameters including at least one of the gap, an attraction pressure of the first substrate by the first holder, an attraction pressure of the second substrate by the second holder or a pressing force on the first substrate by the striker, based on trend information indicating a tendency of a change in the direction and the degree of the distortion when each of the multiple parameters is changed and the inspection result acquired in the acquiring of the inspection result.