We studied the lattice constant and atoms substitution tunable topological phase transition in the half-Heusler compounds HfIrX (X=As, Sb, Bi). At the equilibrium cubic crystal structure and excluding SOC, HfIrAs and HfIrBi are topological nontrivial semimetal, while HfIrSb is a trivial topological insulator. This is because that the “internal pressure” lifts the s-type Γ1 band above p-type Γ5 bands in HfIrSb. When SOC is included, HfIrAs and HfIrSb become topological insulator, and normal band insulator, respectively, while HfIrBi is still a topological semimetal. When we induce compressive stress in the ab-plane of HfIrBi, it becomes a Weyl semimetal, with eight Weyl-Points (WPS) at (±Kx, 0, ±Kz), (0, ±Ky,±Kz), Kx=Ky=0.023Å−1, Kz=0.108Å−1.