Abstract: The imaging T-matrix method is proposed to semi-analytically solve the acoustic scattering from the finite cylinder with hemisphere endcaps in wedge-shaped waveguide. Based on the mirror imaging principle, the acoustic scattering from the finite cylinder under the point source incidence in wedge-shaped waveguide is equivalent to acoustic scattering from multiple cylinders under multiple point source incidence in free space. Then, the transition matrix (T-matrix) of finite cylinder in wedge-shaped waveguide can be obtained using the translation and the rotation addition theorems of spherical wave functions. Therefore, the solution to the acoustic scattering from this cylinder can be semi-analytically solved. Besides, the influences of some related parameters on the backscattering and the distributions of the scattering field are studied, such as source position, target attitude, immersion depth and the inclination angle. The method proposed in this work can be further extended for the analysis of the acoustic scattering from multiple targets in shallow water waveguide.