Column core of protective column

The invention relates to the field of liquid chromatography, in particular to a protection column core which comprises an upper sealing body, a lower sealing body, a sealing pipe and a cap body, the upper sealing body and the lower sealing body are used for sealing openings in the two ends of the sealing pipe. The upper sealing body is provided with a first opening, the lower sealing body is provided with a second opening, and a first sieve plate is embedded in the second opening; the cap body is provided with a third opening, a second sieve plate is embedded in the third opening, and the cap body is in threaded connection with the upper sealing body so that the lower end of the second sieve plate can stretch into the first opening. The column core provided by the invention still has the capability of conveniently replacing the filler in a relatively small size, so that the experiment and detection cost is effectively reduced. 本发明涉及液相色谱领域，特别涉及一种保护柱柱芯，包括上封体、下封体、密封管和帽体；所述上封体和下封体用以封闭所述密封管的两端开口；所述上封体设有第一开口，所述下封体设