Granular CoCrPt-SiO₂ thin films with Cr underlayers have been fabricated by sputtering followed by post-deposition annealing. Microstructural and magnetic properties of as-deposited and annealed films have been investigated for potential applications in magnetic recording media. The grain size of about 10 nm was obtained in the as-deposited films, and subsequent annealing did not lead to significant grain growth. High coercivity up to 5640 Oe was achieved upon annealing. The M_rt value can be down to about 0.4 memu cm^-2 for films with H_c exceeding 5000 Oe. The peak value of the delta M curves changed from a positive value in as-deposited films to a negative value for annealed films, indicating an obvious reduction of intergrain magnetic exchange coupling after annealing.