The effects of subphase pH and temperature on the interfacial aggregation behavior of two amphiphilic hyperbranched poly(methacrylic acid-co-lauryl methacrylate) (H-P(MAA-co-LMA)) copolymers at the air/water interface were investigated by the Langmuir film balance technique. The structures of their Langmuir–Blodgett (LB) films were investigated by atomic force microscopy. At the air/water interface, each molecule of H-P(MAA59%-LMA) and H-P(MAA48%-LMA) (weight percent) tend to form 91 and 67 sub molecular micellar domains, respectively, and each main chain carbon backbone forms 13 and 8 cores, respectively, and each core contains 11 and 13 methylene groups, respectively, and each micelle shell contains 0.8 and 1.3 ester groups, respectively, and 3 carboxyl groups. Under the same subphase pH conditions, the limiting areas (A0) of the surface pressure-molecule area isotherms of the former copolymer are smaller than those of the latter one due to the larger monolayer compressibility probably mainly resulted from the slightly less dense network monolayer structures. Furthermore, for H-P(MAA59%-LMA), the A0 values of its isotherms at different pH values are close, showing negligible pH effects. However, for H-P(MAA48%-LMA), the A0 values of its isotherms first decrease and then increase with the increase of subphase pH values probably due to the decreased steric hindrance and the increased electrostatic repulsions, respectively. With the rise of temperature, the isotherms of H-P(MAA59%-LMA) at different pH values mainly exhibit shrinking effect probably caused by the break of hydrogen bonds between carboxyl/ester groups and water molecules, whereas those of H-P(MAA48%-LMA) under neutral and alkaline conditions at 30 oC exhibit significant expansion effect probably due to the large micelle shell density and the significant increase of molecular thermal motion.