In the field of automatic control, using a microprocessor application system to monitor and control an automatic system is quite common and its usage rate are still increasing. Microprocessor can support complex processes scheduling, and accurately control on time and position. However, even a highly professional programmer still needs a lot of time to maintain the control programs running on this kind of control system. The advent of the programmable logic controller (PLC), which consists of CPU, data memory, digital and analog I/O port, and power module provides an alternative for designing an automatic system. It¡¦s used in the field of industrial control widely. Compared to the microprocessor-based control systems, the PLC-based control systems have the advantage of providing a development environment for easily programming and maintaining. However, the high cost, poor signal processing ability, and the restriction on the function of device are the major drawbacks of PLC. To solve the problems described above, this paper taking the advantages from the PLC-based microprocessor-based control systems proposes a PLC-like development environment for creating a microprocessor- based control system. To accomplish this goal, according to the object- oriented concept, this paper classified the device in a microprocessor into four categories, GPIO, ADC, Timer and Serial-com. And also provides an interface window for users to set and access device register. In addition, this paper provides a set of user customizable task module tools to easily establish a PLC-like based system. Then system developers can write a program via a simple event-table-driven way, and build up the operating procedures according to the approach of sequential multitasking. Our research result make the building of microprocessor-based system can be clearly divided in to three stages, microprocessor manufacturer, advance user, and generally user which not only makes the development of product easier and faster but also meets the time-to-market demands. In the future, some advanced technologies can be added into this automatic controller development tools to make it smarter and more automatic. For example, the environment can support the developed technology for multi-thread and multi-core microprocessor to analysis and establish Instruction trace, and adjust the load balancing automatically. Or it can integrate the graphical programming allows users to program simpler and more intuitive.