This is the famous 洛阳铲, or luoyang shovel, one of the most important tools in Chinese archeology. The basic idea is that you take it and shove it in the ground and then pull it up and look to see if you have found something. It is particularly handy for finding the rammed earth walls that mean you have found a settlement of some sort. The thing I find interesting about it is that the shovel was originally invented by grave-robbers i.e. bad people who wanted to find ancient relics and sell them for money rather than use them in the name of science and preserving the national past and tenure. It was borrowed by real scholars and they started to use it.
Not to take anything away from important early scholars like Li Ji, K.C. Chang and others, but of course a lot of early, especially 19th century archeology was little more than looting by modern standards, so it is not all that surprising that the two groups would borrow from each other. The nice thing about the luoyang shovel is that it lets you do modern survey archeology, and even do it underground, without having to disturb the site very much or waste a lot of time. Grave robbers could use it to do quick, unobtrusive little investigations that would tell them where to come back and dig for real. Modern scholars can do the same thing. Of course in some ways it is a more useful tool for scholars, which I find a bit ironic. You can use it to measure the size of a town wall without having to dig the whole thing up, or to map out the location of different parts of a site without needing to dig them up. It is actually better for producing knowledge than for producing salable artifacts.