Recently, the SARS-CoV-2 Omicron has spread very quickly worldwide. Several studies have indicated that the Omicron variant causes a substantial evasion of the humoral immune response and the majority of existing SARS-CoV-2 neutralizing antibodies. Here we address this challenge by applying a spherical cocktail neutralizing aptamer-gold nanoparticle (SNAP) to block the interaction of Omicron receptor binding domain (RBD) and host Angiotensin-Converting Enzyme 2 (ACE2). With the synergetic blocking strategy based on multivalent multisite aptamer binding and steric hindrance by the size-matched gold scaffold, the SNAP conjugate tightly binds to Omicron RBD with a dissociation constant of 13.6 pM, almost completely blocking the infection of Omicron pseudovirus with a half-maximal inhibitory concentration of 35.9 pM. Overall, the SNAP strategy not only fills the gap of the humoral immune evasion caused by clustered mutations on Omicron, but also provides a clue for the development of new broad neutralizing reagents against future variants.