The invention discloses a four-dimensional automatic scan method of measuring a complex / dynamic 
dose field, and a four-dimensional automatic scan water tank 
system. The four-dimensional automatic scan water tank 
system mainly includes a 
motion control unit, a 
dose measuring unit, an automatic self-positioning unit, computer 
application software, a case, a supporting rod, a water tank, etc. Compared with conventional 
water tanks, the 
system has the following advantages: 1) four-dimensional measuring 
control software is designed to achieve a new four-dimensional measuring function; 2) a 
linear array and a flat-panel 
detector are utilized to improve the measuring efficiency; 3) the system is provided with a water tank automatic self-positioning auxiliary device, so the self-positioning efficiency is increased; and 4) the water tank and an accelerator interface communicate with each other, so the measuring efficiency is increased. The system is capable of measuring complex and (or) dynamic 
dose fields, is a significant measuring tool for research and development of novel 
ray devices and novel 
irradiation technologies and for applications of the device and technologies, and also provides a more accurate platform for discussion of 
organ motion influence and other scientific issues.