Recent investigations in the magnetocaloric effect mainly focus on the discovery of new materials exhibiting large refrigeration capacity, tuneable working temperature and negligible hysteresis. In this context, different magnetic phase transitions of Ni50Mn36Ga x Sn14-x (0 ≤ x ≤ 14) ferromagnetic shape memory alloys have been systematically investigated and the phase diagram with morphotropic phase boundary (MPB) was drawn accordingly. In particular, magnetocaloric effects were calculated and compared in the vicinity of Curie transition, martensitic transition and MPB, respectively. As a result, the magnetocaloric effect of the Ni50Mn36Ga5Sn9 alloy has a wide working temperature range and zero thermal hysteresis at the MPB compared to the effect occurring at other transitions, and the effective refrigeration capacity could reach a compared value 96 J kg-1 in this case. © 2019 The Japan Society of Applied Physics.