The invention discloses a bottom water plugging agent system and a bottom water plugging technology for a horizontal well. The bottom water plugging agent system is characterized in that for the conventional horizontal well, the bottom water plugging agent system consists of an inorganic sediment type system and a polysilicone system or a polymer gelling system, and for the thermal recovery horizontal well, the bottom water plugging agent system consists of the inorganic sediment type system and an N2 foaming system or a temperature sensitive gelling system. The bottom water plugging technology for the horizontal well comprises the following steps that (1) on the basis of determining a water leakage point, the plugging agent system is injected into an annular chemical packer (ACP) by a mechanical packer, so as to ensure the injection selectivity; (2) the plugging agent system is selected according to a temperature and anisotropy parameters of an oil reservoir stored by the horizontal well; and (3) the plugging agent system is injected. The plugging agent system is selected reasonably, and is proper in combination, and high in injection capability; after the technology is applied to the horizontal well with high water content or ultra-high water content, the purpose of high-strength deep plugging can be achieved; a plugging rate reaches 90%; the water content of the horizontal well is reduced effectively; and the productivity of an oil well is increased.