The invention relates to a dynamic memory leak detection method and system. The method comprises the following steps of: dynamically mounting a memory monitoring module in a dynamic link library into an address space of a monitored process by a tool side so as to ensure that the monitored process has a memory leak detection function; recording memory operation behaviors by the monitoring module, putting the messages into a message queue and sending the message queue to an proxy server side; and uniformly managing memory information in the message queue by the proxy server side and sending the memory information to the tool side. According to the method and system provided by the invention, the memory leak conditions in process spaces can be monitored in real time without interrupting target processes, so that real online monitoring is realized; and the memory leak detection can be remotely controlled through the tool side, and the memory information of the monitored processes can be harmlessly read and written by the proxy server side, so that practical value is brought to position memory errors and diagnose problems, and the method and system are suitable for different scenes such as Linux system C/C++ programs, electric power system programs and the like.