LaFe11.85Si1.15 ribbons with large magnetic entropy change and minor magnetic hysteresis were prepared by melt-spinning technique followed by heat treatment. The influences of different heat treatment processes on phase constitution, microstructure evolution, magnetic entropy change, Curie temperature and itinerant electron metamagnetic transitions were investigated in details. It was shown that the annealed processes had a great influence on the content of 1: 13 phase and magnetocaloric effect. For LaFe11.85Si1.15 alloy prepared under the annealed time of 10 h at 1050 ℃, the maximum △SM value of 20.54 J/(kg K) and the refrigerating capacity of 417.21 J/kg can be acquired due to the high content of 1:13 phase in the magnetic field of 0-5 T, and the phenomenon of itinerant electron metamagnetic transition can be observed, obviously. The shorter annealed time is not beneficial in the formation of 1:13 phase. Meanwhile, too long annealing time can also lead to the decomposition of 1: 13 phase and increased of a-Fe phase.