Abstract: Thermophysical properties of molten core materials are necessary input parameters to predict the progression as well as to evacuate the risk of severe accidents in light water reactors. Thermophysical properties of corium are also needed to assess the effectiveness of mitigation strategies, such as invessel and ex-vessel melt retentions, which are preferred in advanced light water reactors. The corium contains the components of UO₂, ZrO₂, Zr and Fe, and the melt temperature can reach around 3 000 K. Due to the high temperature, molten corium property data are limited and very difficult to obtain so far. Aerodynamic levitation is a preferred technique to measure the thermophysical properties of high-temperature oxides. An apparatus based on aerodynamic levitation & laser heating for measurement of density, surface tension and viscosity was described in this paper. The experimental apparatus was named as ALSEE (aerodynamic levitation-laser heating installation for melt properties). ALSEE was composed of aerodynamic levitation system, laser heating system, image recording system, temperature measurement system, acoustic excitation system and data acquisition system (DAS). The first four systems and DAS were built, which were sufficient for density measurement. The acoustic excitation system under installation would be intended for the measurements of surface tension and viscosity. Powders or irregular objects could be melted into a nearly spherical sample by laser heating in a device called laser hearth melter. The laser hearth melter was made of copper and oxide samples with diameter of 24 mm could be made from it. During the actual experiment, a sample sphere was firstly levitated by a conical nozzle, then it was heated into a liquid drop by a CO₂ laser, and the sample shape was recorded by a high-speed camera. A common canny edge detection algorithm was used and the least-squares fitting based on algebraic distances was performed by inverse technique. Finally, the density was calculated from the mass of the sample and the liquid drop volume derived from image post-treatments based on the ellipsoid assumption. As tests before the prototype corium, density of liquid zirconium oxide was measured to be 4.717 g/cm³ at the melting point of 2 988 K while the temperature coefficient was claimed to be -7.202×10^-4 g/(cm³·K) from 2 750 K to 3 200 K.