Abstract: To solve the problem of anisotropy in mechanical properties of arc additive manufacturing, a four-tungsten-electrode heat source additive manufacturing is proposed. Utilize the ultra-high heat input characteristic of quadruple-electrode gas tungsten arc to conduct in-situ heat treatment on the deposited parts based 00Cr13Ni5Mo stainless steel, in order to achieve the transformation from columnar grains to equiaxed grains.The microstructure characteristics of different positions of the deposited parts are studied, and mechanical properties of the deposited parts in different directions and positions are investigated emphatically through tensile and impact tests. The results show that in-situ heat treatment can transform the microstructure of the deposited parts from columnar grains to equiaxed grains, with the average grain size reducing from 44.28 μm to 4.86 μm, significantly improving the anisotropy of the mechanical properties. The microstructure of the deposited parts consists of tempered sorbite, tempered martensite, inverted austenite, and carbide. The average hardness of the deposited parts is (279.4±10) HV10, the yield strength at room temperature is (903.7±11) MPa, and the impact energy at 0 ℃ is (207.6±10) J. In conclusion, the anisotropy of the microstructure and mechanical properties of the deposited parts is minimal. This technology offers a viable solution for improving the anisotropy of the microstructure and mechanical properties in wire arc additive manufacturing.