Density limits with different fuelling methods have been compared in HL-2A, i.e. direct gas puffing and supersonic molecular beam injection (SMBI) from outer midplane, and divertor gas fuelling. The maximum densities for low current discharges are 3.4×10^19 m-3, 4.3×10^19 m-3 and 4.7×10^19 m-3 for the 3 kinds of fuelling methods. The corresponding density ratios to Green- wald density limit are 0.9, 1.1, 1.2, respectively. The behavior of density limit disruption is analyzed as well.