The invention discloses a horizontal well intra-tube segmentation gravel filling sand control tubing string and filling devices. The horizontal well intra-tube segmentation gravel filling sand control tubing string comprises an oil tubing string, a gravel filling tool, a flushing tubing string, sand control sieve tubes, at least one stage of segmentation filling device, inner sealing short sections and a plug, wherein the flushing tubing string and the segmentation filling devices are put into the sand control sieve tubes; each stage of segmentation filling device is matched with the corresponding inner sealing short section. Each segmentation filling device comprises an outer short section and a lower connector connected with the lower portion of the outer short section, wherein an inner core tube is arranged between the outer short section and the lower connector; a conversion sliding sleeve is installed at the upper portion between the outer short section and the inner core tube. A long well section, a large-slope well section or a horizontal well section is filled with gravels more sufficiently and compactly, the sand control effect is good, and the horizontal well intra-tube segmentation gravel filling sand control tubing string and filling device can be widely applied to oil and gas sand control wells.