To obtain the fracture properties of three-point bending concrete beam with double cracks, 24 specimens were tested in this paper. The initial crack-depth ratio of the specimens with a single crack is 0. 4. For the specimens with double cracks, the initial crack-depth ratio of the main crack(MC)is 0. 4 and it is 0. 2~0. 4 for the secondary crack(SC), while the distances between the SC and MC are 120 mm and 160 mm, respectively. Based on the double-K fracture theory, the effect of the crack-depth ratio of SC and the distance between SC and MC on the initial load, the maximum load, and the P-δ curve were studied. The results indicate that, with the increase of the crack-depth ratio of the SC from 0 to 0. 4, the initial load of the specimens increased from 4. 65 kN to 7. 12 kN by 53. 1%, and the maximum load increased from 7. 37 kN to 8. 22 kN by 11. 5%. With the increase of the distance between SC and MC, the initiation load, the maximum load and the ratio of initial load to maximum load increased at first and then decreased. Meanwhile, values of them reached to the peaks when the distance was 80 mm. Compared to single crack specimens, the bigger the ratio of the SC, the larger the slope of the linear segment of measured P-δ curve; the larger the distance between SC and MC, the smaller the slope of linear segment.