The holotype of Sinotyrannus is KZV-001, a disarticulated partial skeleton including the front portion of the skull, three dorsal vertebrae, the incomplete ilia, three articulated manual phalanges (including an ungual), and other fragmentary bones.
In 2010 Gregory S. Paul estimated its length at 9 meters (30 ft) and its weight at 2.5 tonnes (2.75 short tons).
In 2016 it was given a smaller size of 7.5 meters (24.6 ft) and 1.2 tonnes (1.3 short tons).

The preserved cranial elements include the premaxillae, dentary, and anterior portions of the maxillae and nasals.
The dorsal margin of the maxilla is unusually concave unlike the convex condition in tyrannosaurids.
The nares are large and elliptical, supporting its relation to proceratosauridae.
The dentary gradually curves upwards as it approaches its front edge.
Many teeth are preserved attached to the maxillae, with a roughly equal number of denticles on each side, similarly to those of tyrannosaurids.
Sinotyrannus could perceivably have had a tall nasal crest like other proceratosaurids, although not enough of its nasals are preserved to be certain.

The three preserved vertebrae have very tall neural spines.
The proportions of the preserved manual phalanges support the idea that they belong to the second finger, and the ungual has a deep groove on each side.
The ilia are mainly present as molds, with the mold of the external side of the left ilium being the most complete.
The preacetabular blade is short and wide, with a massive pubic peduncle, while the postacetabular blade is longer and thinner, with a triangular ischial peduncle.
These traits of the ilia differentiate it from more advanced tyrannosauroids such as the tyrannosaurids.

Sinotyrannus was among the largest basal tyrannosauroids known, repudiating the previously presumed trend that tyrannosauroids gradually increased in size throughout the Cretaceous period from small basal forms like Dilong to advanced apex predators such as Tyrannosaurus.
The holotype of Sinotyrannus is KZV-001, a disarticulated partial skeleton including the front portion of the skull, three dorsal vertebrae, the incomplete ilia, three articulated manual phalanges (including an ungual), and other fragmentary bones. In 2010 Gregory S. Paul estimated its length at 9 meters (30 ft) and its weight at 2.5 tonnes (2.75 short tons). In 2016 it was given a smaller size of 7.5 meters (24.6 ft) and 1.2 tonnes (1.3 short tons).
The preserved cranial elements include the premaxillae, dentary, and anterior portions of the maxillae and nasals. The dorsal margin of the maxilla is unusually concave unlike the convex condition in tyrannosaurids. The nares are large and elliptical, supporting its relation to proceratosauridae. The dentary gradually curves upwards as it approaches its front edge. Many teeth are preserved attached to the maxillae, with a roughly equal number of denticles on each side, similarly to those of tyrannosaurids. Sinotyrannus could perceivably have had a tall nasal crest like other proceratosaurids, although not enough of its nasals are preserved to be certain.
The three preserved vertebrae have very tall neural spines. The proportions of the preserved manual phalanges support the idea that they belong to the second finger, and the ungual has a deep groove on each side. The ilia are mainly present as molds, with the mold of the external side of the left ilium being the most complete. The preacetabular blade is short and wide, with a massive pubic peduncle, while the postacetabular blade is longer and thinner, with a triangular ischial peduncle. These traits of the ilia differentiate it from more advanced tyrannosauroids such as the tyrannosaurids.
Sinotyrannus was among the largest basal tyrannosauroids known, repudiating the previously presumed trend that tyrannosauroids gradually increased in size throughout the Cretaceous period from small basal forms like Dilong to advanced apex predators such as Tyrannosaurus.
Sinotyrannus