In order to investigate the creep laws and the relation between particle breakage and creep strain of some certain rockfill, a series of constant-stress drained creep tests were conducted on rockfill materials with the large-scale triaxial apparatus. Tests were carried out under different confining pressures and stress levels. Particle breakage degrees of this rockfill were measured by sieve test after creep tests. It is indicated that creep deformation of rockfill has something to do with confining pressures and the stress levels. The axial creep strain and the volumetric creep strain increase with the increase of stress levels, and also increase with the increase of confining pressures under same stress level. The strain-time relation can be described with power function. The stress-axial strain and stress-volumetric strain behavior can be described with hyperbolic and linear function, respectively. Particle breakage degrees increase with the increase of stress levels and confining pressures. The relative particle breakage index can be adopted to descript the particle breakage of rockfill. And the axial creep strain and volumetric creep strain are linearly dependent on this index.