As the development of science and technology day by day, the key control system is more in line with the requirements of people. The paper presents a cryptographic smart password control based on MCU, describes hardware structure and software design of the system. The circuit realizes the intelligent control core which the password locks, it is uses for to complete the password the input, the judgment and the comparison and the execution corresponding next function like unlocks. The password input uses 4×4 the determinant keyboard. Through seven sections of digital tubed to show the correct password.
Experiments show that the password control system is characterized by its reasonable designing methods, simple operation, low cost and property of safety and practicality.Besides,the password control can be used in the office and has great potential for commercial development.