It is well known that the dimple area density is a key parameter for the design of mechanical seal with dimples. In the present paper, the integrated influence of sliding velocity, outlet pressure, and seal clearance on optimum dimple area density, represented by dimple number along the dimple column taken from the seal surface, are conducted theoretically by solving Reynolds equation, where the Floberg–Jakobsson–Olsson cavitation theory is implemented using a mass-conservative algorithm to accurately predict the behavior of cavitation. The results show that the optimum dimple area density is closely related to the operation parameters and the influence of each operation parameter can be divided into three regions. Moreover, for each operation parameter, both of the range of the divided regions and the corresponding values of the optimum dimple area density are strongly associated with the other two operation parameters. In addition, the influences of operation parameters on optimum dimple area density can be investigated by their effects on the maximum pressure caused by dimples.