The operation to evaluate the performance of the vehicle and hence to tune the parameters is made by hand by an engineer in charge of the test vehicle. However, it has the disadvantage that is time consuming and expensive. To compensate for this, this paper studied the automated tuning of parameters. The target vehicle is a vehicle operated by an engine with auto cruise function for tracking a target speed. First, the power train simulator which was verified by the actual driving was made by MATLAB software. For calculating a target speed the power train simulator receives the switch signal and it calculates the required torque accompanying the speed change stage which is designated by calculation based application and also simplified map based application. The shift speed is generally the auto cruise function of parameters of the vehicle wheel speed and the throttle opening degree. A new concept of the vehicle is introduced for the shift pattern, so it is important to keep tracking the target speed, the virtual throttle opening. When the simulation is performed, the target performance data of running the simulator are analyzed and it modifies the required torque and the shift map accordingly. The modified parameters are re-applied to the vehicle which is driven in the virtual environment. This process is repeated until satisfying the required performance. This iterative algorithm is built based on the theory of multi-disciplinary design optimization from the technology management theory. The theory is a feedback process to correct the input of design parameters of the system until the configured objective function satisfying the target performance or the output variable. Performance targets are sure to meet the target time during deceleration of the vehicle, constant torque fluctuation which is not severe, increase or decrease of fuel consumption, engine performance and drivability, such as, fuel efficiency, and the like. The correction of the required torque is determined according to the method applied constant speed, acceleration, From the data according to the running of the simulation, the constant speed drive range is applicable for strategies to fix the gear stage in order to minimize the fluctuation of the torque applied to the engine. For driving period of the acceleration and deceleration, required acceleration functions are adjusted to be applied to the calculated torque demand to meet the target time to reach the target speed. Correction of the transmission pattern is to extract a sample from the constant speed and acceleration data, the process proceeds to driving tuning for each sample. And selecting the first tuning target patterns in each sample and determine the number of stages accordingly. To review the correction, samples are investigated whether the traction-load and driving distance conditions are satisfied. It is not to proceed with the tuning for the sample if the target pattern does not meet the condition. Repeated analysis of the auto-tuning is conducted from the driving data. It can be seen that the vehicle meets the performance. Consequently, engineers automatically tune parameters from computers instead of manually tuning parameters which can be satisfied with vehicle performance expecting increase convenience as the good effect.