The samples of La(Fe1-xCox)11.2Si1.8 (x = 0, 0.02, 0.04, 0.06) have been prepared by ball-milling with elemental powder and LaSi cast master alloys. After sintering at 1423 K for 30 minutes followed by a quenching in water, an almost NaZn13 type single phase has been obtained. The study of magnetic properties revealed that the Curie temperature increases with Co content from x=0 to 0.06 whereas the magnetic entropy change decreases. The alloy of LaFe11.2Si1.8 has a maximum magnetic entropy change △Sm of 6.5 J/kg K near its Curie temperature under a magnetic field of 0-1.5T, while the maximum magnetic entropy change is about 2.1 J/kg K with x=0.06. Furthermore, the magnetization of ball-milled samples exhibits a second-order magnetic transition, which is interesting for magnetocaloric applications.