The utility model relates to a fiber grating hydraulic sensor, comprising a housing; a pressure transmission hollow capsule placed outside the housing and comprising a capsule body and fillers placed in the capsule body, wherein the capsule body is provided with a capsule body opening; a pressure transmission apparatus fixed in the housing and comprising an open end and a movable free end, the open end being in seal connection with the capsule body opening; and a fiber grating strain apparatus with one end connected with the movable free end of the pressure transmission apparatus and the other end fixed in the housing. Compared with a traditional electric hydraulic sensor, the fiber grating hydraulic sensor has the advantages of good anti-electromagnetic interference performance, good electrical isolation performance, wide suitable scope and good chemical performance stability, is safe and reliable and can realize long distance monitoring.