A parameter optimization device includes a data acquisition module, a sampling function calculation module, a clustering module and a parameter recommendation module. The data acquisition module is configured to acquire several input parameter values and corresponding several measurement output values. The sampling function calculation module is configured to obtain several sampling function values according to the input parameter values and the measurement output values. The clustering module is configured to obtain several parameter groups according to the input parameter values and the sampling function values. The parameter recommendation module is configured to obtain several recommended parameter values from at least one of the parameter groups.