The utility model discloses a pressing block locking structure for moving vanes of a steam turbine. The pressing block locking structure comprises a rotor, the moving vanes, pressing blocks, adjusting blocks, locking screws, steel balls and gap cushioning strips and is characterized in that T-shaped vane root grooves are formed in the rotor along the circumferential direction, vane mounting gaps and pressing block mounting grooves are formed at steam inlet sides of specific locations of the vane root grooves, the moving vanes are embedded into the rotor through the gaps and can slide along the circumferential direction, and every two adjacent mounted moving vanes are mounted closely. After a whole ring of moving vanes is mounted completely, the last moving vane is mounted in the corresponding gap, the pressing blocks and the adjusting blocks are mounted, the adjusting blocks are driven into the mounting grooves in an interference manner, so as to compact the pressing blocks, and finally, the locking screws are driven among the rotor, the pressing blocks and the adjusting blocks along a roulette, so that the whole ring of vanes is fixedly arranged. The pressing block locking structure has no need of special tail vanes, has the characteristics of simple structure, convenience in mounting, good fixing effect and the like, is beneficial to the safe operation of the steam turbine and is particularly applicable to the mounting locking of titanium-alloy moving vanes of industrial steam turbines.