Epitaxial growth of Zn-doped InGaAs on InP substrates has been carried out at 550 o C by LP-MOCVD. Hole concentration as high as 6x10 1 9 cm - 3 has been achieved at the H 2 flow rate of 20sccm through DEZn bubbler. The lattice constant of Zn-doped InGaAs was found to be dependent on the flow rate of DEZn, and the tensile strain mismatch increases with increasing H 2 flow rate of DEZn. The negative lattice mismatch of heavily Zn-dopped InGaAs may be due to the small covalent bonding radius of zinc and the combination of butane from ethyl of DEZn and TEGa. And the latter accelerates the pyrolysis of TEGa, which is the dominant mechanism in determining the negative mismatch of Zn-doped InGaAs.