Stress rupture properties and fracture behavior of Ni microalloyed W were studied using direct load creep tester at 100$0^{circ}C$, 110$0^{circ}C$ and 120$0^{circ}C$ in $H_2$. At the same grain size, 15${mu}$m, the 100hr. stress rupture strength of W-0.4wt% Ni was 23% higher than that of W-0.2wt%Ni due to the grain growth during test. The minimum creep rate of W-0.2wt%Ni was decreased with an increase in initial grain size. By increasing the Ni content of Ni microalloyed W, rupture time was increased owing to the smaller number and size of cavity. All the specimens showed intergranular fracture by grain boundary sliding and nucleation, growth and coalescence of cavities at grain boundary.