An SSD-based log data storage method and apparatus, a device and a medium. Said method includes: configuring metadata in a running state in log data to be continuously stored in a memory physical address of an SSD; dividing a preset number of buffers for an area where the metadata is continuously stored in the memory physical address, so that all the buffers have a preset cyclic sequence; storing update data of the metadata generated during a reading-writing process according to the preset cyclic sequence; defining a mapping table of a memory logical address and a physical address of the log data; in response to the full storage of one buffer, executing an NAND writing operation on data in the buffer region, and executing a preset length of NAND writing operation on metadata not written into a NAND in the SSD; and in response to the completion of the NAND writing operation, ranking the corresponding buffer last in the preset cyclic sequence and waiting to store the update data of the metadata. The solution provided by the present disclosure can reduce the complexity of the metadata storage.