The invention discloses 1000 MPa-grade biphase high-strength galvanize strip steel, a steel sheet and a preparation method. The strip steel and a steel sheet base sheet include ingredients of, by mass content, 0.06-0.15% of C, 2.2-2.8% of Mn, 0.45-0.65% of Si, 0.40-0.60% of Cr, less than or equal to 0.012% of P, less than or equal to 0.002% of S, 0.020-0.070% of Als, 0.010-0.030% of Ti, 0.15-0.30% of Mo and the balance Fe and impurities which cannot be removed. The preparation method includes the steps of heating, hot rolling, cold rolling, continuous galvanizing, finishing and passivating. New ingredient design is adopted, production difficulty is greatly lowered by controlling process parameters of all processes, and the yield of a finished product is raised. The finished product has the characteristics of good forming performance, mechanical performance, corrosion resistance performance and the like, and the strength of extension reaches 1000 MPa or above.