Metal halide perovskites have emerged as a promising family of functional materials for advanced optoelectronic applications with high performance and low costs. Various chemical methods and processing approaches have been employed to modify the compositions, structures, morphologies, and electronic properties of hybrid perovskites, great progress has been achieved. Whereas, challenges still remain such as the low stability, the use of environmentally unfriendly chemicals, and the lack of an insightful understanding of the structure-property relationships. In this talk, we will present our efforts in using an alternative means, pressure, to tune the structures and physical properties of halide perovskites. Using state-of-the-art high-pressure techniques coupled with in situ synchrotron-based and in-laboratory property measurements, we characterized the changes in their structural, electrical, and optical properties. Pressure-enhanced properties such as higher electron transport and stronger light absorption, as well as pressure-induced novel phenomena, were observed. Our findings reveal that high pressure can potentially be able to realize enhanced and/or emergent properties of halide perovskites, and further our understanding of the structure-property relationships.