he hot platen needs to be lifted and descended integrally, and to be kept in horizontal level during the process which was realized by position synchronization control of multiple group hydraulic cylinders. It is a difficult point in control of continuous flat press. In order to solve this problem, a ramp type successive approximation algorithm was proposed. The algorithm can dynamically select one group of hydraulic cylinder as “virtual main system”, and the other groups as “slave system” according to the actual displacement of the hydraulic cylinders in any control cycle. Then the virtual main system can gradually approach the target value step by step with a certain ramp. At the same time the slave system tracks the virtual main system in real time, so that it can be realized that the multiple group hydraulic cylinders move synchronously during the lifting and descending process. The algorithm was simulated in Matlab. Then the algorithm was applied to the continuous flat press production line designed by China Foma (Group)Co., Ltd. Production practice indicates that the algorithm can solve the interaction and influence between the multiple group hydraulic cylinders in movement effectively. The synchronous error of the lifting and descending process is 0.5mm and 0.6mm respectively. The shock of hydraulic components is less, the process is smooth and the control precision can meet technological requirements.