The invention discloses an assembly template, comprising an upper groove template, a lower groove template, an internal template and an external template, wherein the internal template is positioned at the inner side of the external template, and a certain distance is formed between the internal template and the external template; the lower groove template is positioned below the position between the internal template and the external template; the upper groove template is positioned above the position between the internal template and the external template; the lower groove template is connected with the external template and the internal template; the upper groove template is connected with the external template, and a gap is formed between the upper groove template and the internal template; the lower groove template comprises a plurality of lower groove straight-section templates and a plurality of lower groove bend-angle templates; the polygonal lower groove template is formed by means of mutually splicing the lower groove straight-section templates with the lower groove bend-angle templates. The assembly template has the advantages that the effects of simple structure, practicability and firmness are achieved; the assembly template can be used for manufacturing box culverts of different sizes by means of assembling the lower groove straight-section templates and the lower groove bend-angle templates, and the installation and disassembly are conveniently performed, so that the construction period of assembling the assembly template is greatly shortened, the template fabrication time is reduced, and the template installation time is reduced.