The invention discloses a resource optimization method and device for a CEPH system. The method includes: determining the OSD equipment number of each mainframe in the mainframe set of the CEPH system as the OSD resource score of the mainframe; calculating the RAM resource score of each mainframe according to the total capacity of the OSD equipment of each mainframe in the mainframe set and the total capacity of the RAM equipment of each mainframe; calculating the mainframe resource score of each mainframe according to the corresponding OSD resource score and the RAM resource score; determining that the MON service allocation priority of the mainframes is higher when the mainframe resource scores are higher, and deploying the MON service according the priority of each mainframe. By the resource optimization method, an administrator only needs to pay attention to the deployment of the OSD equipment, the optimal MON service deploying scheme can be obtained according to the deployment of the OSD equipment, unreasonable deployment, caused by the subjective factors of the administrator, of the MON service can be avoided to a certain degree, and the deployment reasonability of the CEPH system is guaranteed.