This paper presented the optimal design methodology of number and locations of actuators in active vibration control when adopting adaptive fuzzy control. The number of actuators was determined by defining the energy correlative matrix of the modal control force. Based on the total energy of active member forces, the model of optimal locations was studied. The integer coded genetic algorithms (GAs) were adopted to search the optimal locations of the actuators in large discontinuous structures. Finally the simulations of a space smart truss were done, and the results showed that the integer coded genetic GAs and adaptive fuzzy active vibration control were effective.