The major purpose of the study is try to solve the problem of manufacturer cannot delivery their products on time. A computer scheduling system based on standard time is developed in the study. The scheduling system can obtain delivery time rapidly of a new order according to standard time of all orders plus a suitable allowance. The production scene needs to feedback the starting time and finish time of all orders in order to re-scheduling all orders. Where there is a delay, there is a quick response from the system. Finally, a simulation validate that a fit standard time, a good production feedback system and an appropriate allowance are the basis for the products can achieve the goal of on time delivery.