Abstract: The growth of high-quality InGaP/GaAs heterostructures on (001) GaAs substrates by gas source molecular beam epitaxy (GSMBE) was investigated. InGaP epilayers with lattice mismatch △α/α ＜ 8.95 × 10^-5 and residual carrier concentrations as low as 1015cm^-3 were obtained. The controllable carrier concentration region for Si-doped n-type InGaP is from 2 × 10¹⁵ to 4 × 10¹⁸cm^-3. The influence of the method to change the group-V molecular beams from As₂ to P₂(or from P₂ to As₂) was studied in order to obtain an abrupt heterointerface. The InGaP/GaAs heterojunction bipolar transistors (HBTs) prepared by using the heterostructures grown by GSMBE in this work exhibit excellent static and high-frequency performance, with the cutoff frequency f_T=25GHz, the maximum oscillation frequency f_max=46GHz, the current gain β=40 with the highest β=150.