The MLPB modified acrylate latex pressure sensitive adhesive(PSA) was synthesized via seed semicontinuous emulsion polymerization, using Maletic Anhydride grafted liquid Polybutadiene (MLPB) as crosslinking modification additives. The reaction mechanism of polymerization system, the influences of the MLPB content on the water resistance , thermal stability and adhesive properties of latex film were respectively investigated. The modified acrylate latex were then characterized. The results show that the latex with ω(MLPB)=5% make the latex film possess the best adhesive performance and water resistance, which the water absorption of latex film was 2.86%; The result of fourier transform infrared spectra(FTIR) indicates that it appears the copolymerization crosslinking reaction during the process of latex modification; The result of Contact Angle meter(CA) shows that the contact angle of latex film with ω(MLPB)=5% reaches to the maximum which is 108? The result of differential scanning calorimetry(DSC) reveals that the compatibility of the modified polymer system is well and the Tg of the latex film is gradually raised as the increase of MLPB content; The result of thermogravimetric analysis (TGA) demonstrates that the modified latex film own better thermal stability.