The invention discloses carboxylic butadiene-styrene latex. The carboxylic butadiene-styrene latex is prepared from the components of styrene, butadiene, acrylic acid, seed glue, an emulsifier, a functional monomer, sodium pyrophosphate, mercaptan and a chelating agent ammonium persulfate. The invention further discloses a preparation method of the carboxylic butadiene-styrene latex, wherein an ultrasonic irradiation device is arranged on the side wall of a reaction kettle, during reaction, the power is 600-1000W, the ultrasonic frequency is 60-80khz, and the power density of sound waves can be 2-5w/cm<2>. The carboxylic butadiene-styrene latex has the beneficial effects that the reaction efficiency can be effectively improved, the side reactions can be reduced, the monomer conversion rate can be increased to over 99%, the reaction time can be shortened by 4-7 hours, the recycled monomer amount can be reduced greatly, the energy consumption is reduced, the damage on the residual monomer to the system stability and the environmental protection can be eliminated to the greatest extent, the performances such as tensile strength, abrasion resistance, bonding strength, washing resistance, alkaline resistance and pollution resistance are excellent, and the mechanical stability and the chemical stability are excellent.