The invention discloses a one-steel multi-stage cold rolling low-alloy high-strength steel strip and a production method thereof. The production method includes the steps of plate blank heating, hot rolling, laminar cooling, acid rolling, continuous annealing and leveling; and the steel strip comprises, by weight percentage, 0.06%-0.10% of C, 0.15%-0.30% of Si, 1.10%-1.30% of Mn, not larger than 0.020% of P, not larger than 0.015% of S, 0.020%-0.060% of Als, 0.045%-0.060% of Nb, not larger than 0.0060% of N and the balance iron and inevitable microelements. According to the method, the composition design idea of low carbon, Nb microalloying and Si and Mn solid solution strengthening is adopted, through reasonable composition design and cooperation with the hot rolling, acid rolling and continuous annealing processes, the aim of obtaining a product with multiple properties through one ingredient is achieved; and the thickness specification of the obtained low-alloy high-strength steel strip is 0.8 mm to 2.5 mm, the yield strength stage covers 420 MPa to 500 MPa, and the ductility A 80 is larger than or equal to 14%.