We have studied chalcogenide Ni1-xFexGa2S4, showing geometrical frustration effect. M-H curves at 4.2 K reveal that the disordered spins cannot be rotated completely along the direction of high external field of 5 T, since these spins are strongly constrained in the triangular lattice. HC increases with increasing Fe concentration, being consistent with the enhanced antiferromagnetic (AFM) spin-spin interactions and the suppressed spin-fluctuation due to the increase in freezing temperature Tf. The specific heat (CP/T) measurement do not show any phase transformation between 2 and 160 K and there is no clear indication of gap in the temperature dependent CP curve between 0 and 7 T, because the atomic short-range ordering of the strained spin in the geometrically frustrated triangular lattice exists at low temperature. Though typical geometrically frustrated magnet shows degeneracy, Mossbauer analysis at 4.2 K shows that 5D of 3d orbit in the samples studied here is splitted into 5T2g and 5E2g, and 5T2g is further splitted into singlet and doublet by large electric quadrupole splitting. This suggests that Fe2+ ionic state has no absolute degenerate energy states in all samples due to Jahn-Teller effect.