Packaging and sealing is the key link to ensure the quality and safety of milk. Poor or irregular sealing may lead to bacterial growth, oxygen entry, water entry and other problems, affecting milk quality and shelf life. Packaging sealing reliability is of great importance to consumers and manufacturers. This study analyzed the key reasons why packaging sealing materials are not easy to monitor. After a number of practical tests, it finally realized the use of ultrasonic sensor technology, hardware installation design in practical application scenarios and automatic control program to solve the monitoring problem of milk packaging sealing materials, overcome difficulties and fill the gaps in the industry. This is meaningful for ensuring product quality and safety, improving production efficiency and reducing labor costs.