This work is to control the fluxes of the Ga, In and Al sources in our MBE system to grow lattice-matched InGaAs, InAlAs and InGaAlAs epi-layers on InP substrates. With the As overpressure condition in the MBE system, we can control the temperature of Ga K-cell to modulate the flux of Ga. In ideal situation, the flux of Ga has a direct ratio with the GaAs growth rate on GaAs substrate, so we can find the Ga flux dependence on temperature by measuring the RHEED oscillation frequency. From the growth rate data of InGaAs on GaAs substrate at lower In composition, the In flux was obtained by comparing the growth rate ratio to the GaAs case. In the same way, we can also get the flux of Al by the growth of AlAs or AlGaAs on GaAs substrate. With the results of flux experiment, we can modulate the temperature of Ga, In and Al K-cells to compose InGaAs, InAlAs and InGaAlAs lattice-matched on InP substrates. The epi-layer quality was examined by X-ray diffraction and photo-absorption spectrum. We have built the flux equations for the Ga, In and Al sources from the experiment data. With the In K-cell temperature at 833~836¢J, Ga(1) at 931¢J and Al at 1094¢J, we have grown ternary compound semiconductors of In0.532Ga0.468As and In0.523Al0.477As lattice-matched on InP substrates. When the In K-cell temperature at 833~836¢J, Ga(2) at 912¢J and Al at 1059¢J, a quaternary compound semiconductor of In0.527Ga0.245Al0.228As (Eg=1eV) lattice-matched on InP substrate was demonstrated.