The invention discloses a nylon-polymethyl methacrylate alloy microbead, which contains the following components in percentage by weight: 30-90 wt% of nylon microbead and 10-70% of polymethyl methacrylate. The alloy microbead uses the nylon microbead as a framework, the interior of the nylon microbead is of a through-hole structure, and polymethyl methacrylate is uniformly dispersed in the pores and/or on the surface of the pourous nylon microbead. The alloy microbead is a spherical or near spherical particle with a particle size of 1-100 mum. In the alloy microbead provided by the invention, a large amount of amido bonds, carboxyl groups and amino groups in the porous nylon microbead are easy to form hydrogen bonds with the ester group in polymethyl methacrylate, and the two components are crosslinked to form an interpenetrating network. The nylon-polymethyl methacrylate alloy microbead has good compatibility with no need of a compatilizer.