A monitoring structure and a relevant monitoring method for the silicon wet etching depth are provided. The structure includes a wet etched groove formed on a monocrystalline silicon material with at least two top surfaces thereof being rectangular; and the top surface widths of the grooves are Wu and W1 respectively, Wu=du/0.71, and W1=du/0.71, where du is the maximum wet etching depth to be monitored, and d1 is the minimum of the wet etching depth to be monitored. The method includes: performing anisotropic wet etching on a monocrystalline silicon wafer according to a pattern with a monitoring pattern, forming an etched groove to be monitored and a structure for monitoring the depth of the groove, and then monitoring the structure to monitor the wet etching depth. The etching depth of the groove can be monitored with low costs, and a higher monitoring accuracy is obtained.