This paper designs web-based USB 1-N wireless I/O modules embedded sequential controller. The controller consists of ARM-based core system, a set of USB 1-N wireless I/O data acquisition modules, and sequential control software. The ARM-based core system running Linux operation system forms the basic hardware/software foundation of the controller. The set of USB devices used as I/O interface (sensor and actuator) of the controller. With the use of RF chip, the USB I/O is cascaded by wireless 1-N channel such that multiple data acquisition modules can communicate with the controller by a USB port. The device driver of the USB set for the ARM-base Linux system is developed. The sequential control software is designed as client/server structure. The server-side program and client-side program communicate through the Internet. The server-side control program, mainly a PLC interpreter, is an application developed in C++ in the Linux system. The client-side control program is developed in Java and put under a web server of the controller such that the program can be easily deployed by network and run in remote computer. The client program is also used as GUI of the controller.