Abstract: In order to meet the application requirements，a new on-boarding method by modifying the existing automatic developing machine is introduced. Based on the automatic developing machine which is currently widely used，the design can transform the in-door working mode of the developing machine to engineering automobile mode and meet the needs of field condition. Through the application of engineering practice, it shows that the machine has the advantage of high efficiency with stable performance, and it can meet the requirements for high processing quality and for project with tight schedule of X-ray detection.