To be able to determine the connection between mechanical property and fracture conduct of UHSC and examine its influencing elements, a sequence of UHSC with completely different combine proportion have been ready. The mechanical properties (together with compressive power, flexural power, and splitting tensile power) had been examined on a hydraulic servo common testing machine. Three-point bend loading technique was used to measure the fracture parameters (together with fracture toughness and attribute size) and a crack was prefabricated within the pattern. The outcomes present that the power of UHSC decreases with w/b ratio and the utmost compressive power and flexural power can attain 132 MPa and 21.5 MPa, respectively. UHSC shows important brittle fracture conduct and its brittleness will increase with power. The principle cause is that the micro-defects of UHSC are decreased and the homogeneity of the entire cement matrix is enhanced, thus the crack initiation power is improved however crack resistance capacity is impaired. Excessive temperature curing will increase the power in addition to brittleness of UHSC. Including fly ash will enhance its attribute size however cut back the facture toughness. Our work could present steering for decreasing the brittleness of ultra-high power concrete.