The invention discloses a method for preparing a burning-free cement brick with improved strength by taking a waste molding compound as an aggregate. The method is characterized by comprising the following steps: S1, screening and proportioning materials; S2, carrying out mixing and stirring, namely mixing the following components in parts by mass: 1 part of standard cement, 2 parts of waste molding compound powder after drying treatment, 0.5 part of river sand, 0.2 part of lime, 0.125 part of a naphthalene-based superplasticizer and 0.01 part of an early-strength agent, and conducting stirring in a water cement ratio of 0.5 so as to obtain a prefabricated product; S3, carrying out molding; and S4, carrying out demolding and maintenance. By adopting the method, a waste molding compound material can be efficiently treated and utilized, natural sand resources are saved and protected, due to adoption of the naphthalene-based superplasticizer, the infiltration effect of a liquid material upon a filler is improved, the utilization rate of the waste molding compound is further increased, the strength of a finished product can be increased, and certain economic benefits can be made.