The invention relates to a road traffic expressway precast T-beam convenient for drainage. The road traffic expressway precast T-beam convenient for drainage comprises a top flange, a drainage pipe, asliding block and a bottom flange; the left and right ends of the top flange are both connected with top flange longitudinal connecting ribs; the front and rear ends of the top flange are both connected with top flange transverse connecting ribs; a convex block is fixed at the bottom end of the top flange; a groove is formed outside the convex block; a web is placed outside the groove; the drainage pipe runs through the top of the top flange; a sealing block is arranged above the drainage pipe; the sliding block is arranged at the bottom end of the web; a sliding track is mounted under the sliding block; the bottom flange is placed under the sliding track; a horseshoe is fixed on the right side of the bottom flange. The road traffic expressway precast T-beam convenient for drainage has the advantages that the flow of accumulated water can be very well guided by using the arranged drainage pipe to prevent the accumulated water from being piled above the precast T-beam so that the construction quality is guaranteed.