The invention provides a low-expansion antioxidative Ni-Fe-Cr-based high temperature alloy and a preparation method thereof. The alloy comprises 20 to 25% of Fe, 14 to 18% of Cr, 1.5 to 2.0% of Al, 1.5 to 2.5% of Ti, 0.5 to 2.0% of Nb, 0.3 to 2.0% of Mo, 0.5 to 2.0% of W, no more than 1.0% of Si, no more than 1.0% of Mn, no more than 0.5% of Cu, no more than 0.1% of C, no more than 0.01% of B, no more than 0.05% of Zr, no more than 0.05% of P and no more than 0.20% of a rare earth element, with the balance being Ni. The alloy is of a double-phase structure, wherein a substrate is an austenite (gamma) phase with a disordered face-centered structure, and a gamma' [Ni3(Al,Ti)] phase with an ordered structure is dispersed in the austenite. According to the invention, on the basis that structural stability, corrosion resistance and high temperature strength of the alloy are not influenced, the content of Fe is increased as much as possible to improve hot workability of the alloy and reduce cost. Compared with the prior art, the alloy provided by the invention has the advantages of low material cost, a low thermal expansion coefficient, excellent high temperature strength, hot-working performance and anti-oxidation corrosion and in particular, better cost performance when used under the conditions of high temperature, high pressure and supercritical water vapor.