The detrital composition is one of the key factors affecting the diagenesis and reservoir physical properties of tight sandstone reservoirs. In order to find out the control mechanism of the deformable compositions on the reservoir, taking the Shanxi Formation in the H well area of the Daniudi gas field as an example, through microscopic observation and statistics of rock thin section, combined with the physical properties, we analyse the controlling effect of deformable compositions on diagenesis, and then discuss their control and mechanism on the reservoir. The results show that the plastic composition of the Shanxi Formation is a tuffaceous matrix, and the semi-plastic compositions include tuff, slate, phyllite, schist, and mudstone detritus. The deformable components mainly control the reservoir through compaction and dissolution, and the compaction pore reduction rate is positively correlated with the content of deformable compositions, in which the effect of tuffaceous matrix on the compaction pore reduction is relatively obvious; the dissolution pore enhancement rate is negatively correlated with the content of semi-plasticity and weakly positively correlated with the content of tuffaceous matrix. The content of deformable compositions is negatively correlated with reservoir physical properties, with the fully plastic tuffaceous matrix having a weaker destructive effect on reservoir physical properties. The deformable compositions exacerbate the densification of the reservoir during compaction, and at the same time reduce the flow of diagenetic fluids, but the tuffaceous matrix completely fill the intergranular pore space after compaction, and the effect is more significant. The tuffaceous matrix as the solute of intergranular dissolution, its dissolution is also conducive to the improvement of the physical properties of the reservoir; when the content of the tuffaceous matrix ranges between 8%～12%, it is the most conducive to the formation of better quality reservoirs.