By studying the electrochemical impedance spectrum variation law of different building solid wastes（aerated brick， red brick， mortar）， the key information and parameters are extracted from the Nyquist curves， combined with the mechanical properties and mercury pressure test data， and the relationship between the impedance spectral parameters and mechanical properties and microstructure was revealed. The results show that the higher the compressive strength of the solid waste， the greater the charge transfer resistance（R_ct2）， and they have a linear relationship. In addition， the more soluble salts of the material， the smaller the pore solution resistance（R_s）， the R_s value of the mortar is below 0.3 Ω， and the R_s value of aerated bricks and red bricks are greater than 55.0 Ω. The size of the specimen affects the contact resistance between the specimen and the electrolyte， mainly reflected in the change of the arc diameter in the high-frequency region， the larger the specimen， the smaller the arc diameter of the high-frequency region. The intrinsic relationship between the impedance spectrum parameters of the building solid wastes and the compressive strength and porosity established can realize the intelligent detection and rapid evaluation of the performance of the building solid wastes.