The invention discloses a concrete axial tension fixed-section breaking device and method. The concrete axial tension fixed-section breaking device comprises a base, a drive mechanism, a clamping groove and a clamping mechanism; by putting a concrete specimen in the clamping groove as well as fixing the drive mechanism and supporting the clamping groove through the base, through clamping and fixing of the clamping mechanism, a broken surface is positioned; the clamping groove is driven by the drive mechanism to perform rotary tensioning breaking; and data is recorded through a laser device. The concrete axial tension fixed-section breaking device provided by the invention overcomes the problem that the randomness at the broken part of the original specimen is large to cause inaccurate testdata, has the characteristics of simple structure, realizing of fixing of the broken section of the specimen at a fixed point, reduction in the influence of random error and capability of accuratelycalculating the tensile strength of the concrete and the method is precise in positioning the section, convenient to operate and accurate in specimen data.