In the future, the extraterrestrial human activities, such as resources exploitation and base construction beyond the Earth need the aid of geotechnical engineering technology. Currently, there are only two approaches for humans to obtain the rock samples beyond the Earth: sample-return activities by spacecraft and meteorite investigation. Meteorites are rare, expensive, small and arbitrary in shape, so it is difficult to process them into standard rock samples required by MTS and other traditional macroscale rock mechanical tests. In this paper, a novel technique for measuring mechanical property of small-size meteorites was developed based on microscale rock mechanics experiments (micro-RME) and statistical probability models. Firstly, the composition, content and distribution of rock-forming minerals in NWA13618 meteorites were obtained by TIMA. Then, Gaussian mixture model was used to calculate the mechanical parameters of four main minerals in meteorite NWA13618. The elastic moduli of olivine, pyroxene, Fe-Ni and feldspar are 116.73, 101.77, 87.24 and 70.74 GPa, respectively. Lastly, the homogenization method Mori-Tanaka model isapplied to calculate the macroscale centimeter elastic modulus of NWA13618 meteorite is 90.48 GPa according to the achieved mineral content and mechanical properties. The microscale rock mechanical experiment and scale upgrading method proposed in this paper provide theoretical basis and technical means for predicting the mechanical properties of L4 parent asteroid.