The phases and magnetocaloric effect in the alloys Tb (Co1 - xSnx) 2 with x = 0, 0.025, 0.050, 0.075, 0.100were investigated by X-ray diffraction analysis and magnetization measurement. The substitution of Sn in TbCo2 was limited. The cubic MgCu2-type structure for the sample of TbCo2 was confirmed by the results of X-ray powder diffraction and the rest samples consist of the TbCo2 phase mainly, together with some TbCo3 and Tb5Sn3 impurity phases. The impurity phases increase with the increase of Sn contents. The magnetic phase transition in all samples keeps second-order transition. TC increases slightly by Sn substitution from 230 K of the alloy with x = 0 to 233 K of the alloy with x = 0. 050 and then a slight decrease for higher concentration of x. The maximum magnetic entropy change in the samples Tb (Co1- x change from 0 to 2.0 T.