The invention discloses a columnar water holding rate detection probe based on electromagnetic waves. The columnar water holding rate detection probe comprises a bottom mounting base, a square locking column and a spiral groove cylinder which are integrally formed from bottom to top. An external thread for being in locked connection with an electromagnetic wave water holding rate instrument casing is arranged in the circumferential direction of the bottom mounting base, and 6 parallelly arranged T-shaped spiral grooves are formed in the circumferential direction of the spiral groove cylinder. The bottom mounting base and the central position of the square locking column are provided with line block mounting holes, the ends of the T-shaped spiral grooves are communicated with the line block mounting holes through 6 inclined line holes formed in the circumferential direction of the bottom of the spiral groove cylinder, and the other ends of the T-shaped spiral grooves are in two-to-two corresponding communication with 3 horizontally parallel line holes formed at the top of the spiral groove cylinder. The columnar water holding rate detection probe is small in mounting dimension and high in resolution ratio, can meet the design requirements of array type instruments suitable for highly-deviated wells and horizontal wells, and is simple in structure, convenient to use and important in practical significance.