The present invention provides a photovoltic and thermal (PVT) heat pump system capable of achieving day-night time-shared combined cooling, heating and power using solar radiation and sky cold radiation. The system utilizes a photovoltaic power generation technology and a photovoltic and thermal (PVT heat pump technology simultaneously, both of which are relatively independent and promoted to each other in the function. The main energy sources of the system are solar radiation energy and sky long-wave cold radiation energy, and the energy is respectively transformed into electric energy, thermal energy and cold energy via a photovoltic and thermal (PVT) photoelectric-evaporation/condensation module at different times in different working modes. The system of the present invention integrates power generation. heating, refrigeration and many other functions; and the equipment has simple composition, high utilization rate and remarkable energy-saving effect, thereby improving the energy utilization rate to the maximum extent, and achieving a multi-purpose machine and day-night time-shared combined cooling, heat and power.