Effects of Nd-doping on the magnetic properties and magnetocaloric effects (MCEs) of NdxLa1-xFe11.5Al1.5 have been investigated. Substitution of Nd leads to a weakening of the antiferromagnetic (AFM) coupling and an enhancement of the ferromagnetic (FM) coupling. This in tu results in a complex magnetic behaviour for Nd0.2La0.8Fe11.52Al1.5 characterized by the occurrence of two phase transitions at ～188 K (PM-AFM) and ～159 K (AFM-FM). As a result, a table-like MCE (9 J/kg·K) is found in a wide temperature range (160-185 K) for a field change of 0-5 T around the transition temperature, as evidenced by both the magnetic and calorimetric measurements. Based on the analysis of low-temperature heat capacity, it is found that the AFM-FM phase transition modifies the electron density significantly, and the major contribution to the entropy change comes from the electronic entropy change.