Sand prevention plugging device

The invention relates to the technical field of wellhead blowout preventers, in particular to a sand prevention plugging device which comprises an upper connector, a lower pipe assembly, an inner push rod and a drill bit, the lower pipe assembly is formed by splicing three inner connecting pipes, each inner connecting pipe is sleeved with an outer connecting pipe, and a main plugging assembly and an auxiliary plugging assembly are arranged in each inner connecting pipe; the main plugging assembly comprises a first plugging block, two sets of top stop blocks are symmetrically arranged above the first plugging block, the auxiliary plugging assembly comprises two rows of second plugging pieces which are distributed in a petal-shaped staggered mode, the outer walls of the multiple second plugging pieces located on the upper row are connected with upper pushing blocks in an abutting mode, and the upper pushing blocks stretch into the inner connecting pipe and are connected to the first starting assembly; a second