The construction of generalised spherical fuzzy number(GSFN)is a reliable philosophy to design and understanding of vagueness and impreciseness.In this study,at first,the authors have defined the generalised spherical fuzzy set and discussed its several properties.Then,a new score and accuracy functions have been introduced in the generalised spherical fuzzy environment which leads to a new method of conversion of fuzzy number into a crisp number.New exponential operational law has been defined for GSFNs where the bases are positive real numbers&components are GSFNs and its various algebraic properties have been studied explicitly.Using this exponential operational law,a generalised spherical weighted exponential averaging operator has been proposed,which is used to develop a multi-criteria group decision-making(MCGDM)method in the generalised spherical fuzzy environment.The newly developed MCGDM has been demonstrated through a real-life problem and its effectiveness and rationality have been shown through sensitivity analysis.